🏗 Merge C++ into python codebase (#504)

## Description:

Move esphome-core codebase into esphome (and a bunch of other refactors). See https://github.com/esphome/feature-requests/issues/97

Yes this is a shit ton of work and no there's no way to automate it :( But it will be worth it 👍

Progress:
- Core support (file copy etc): 80%
- Base Abstractions (light, switch): ~50%
- Integrations: ~10%
- Working? Yes, (but only with ported components).

Other refactors:
- Moves all codegen related stuff into a single class: `esphome.codegen` (imported as `cg`)
- Rework coroutine syntax
- Move from `component/platform.py` to `domain/component.py` structure as with HA
- Move all defaults out of C++ and into config validation.
- Remove `make_...` helpers from Application class. Reason: Merge conflicts with every single new integration.
- Pointer Variables are stored globally instead of locally in setup(). Reason: stack size limit.

Future work:
- Rework const.py - Move all `CONF_...` into a conf class (usage `conf.UPDATE_INTERVAL` vs `CONF_UPDATE_INTERVAL`). Reason: Less convoluted import block
- Enable loading from `custom_components` folder.

**Related issue (if applicable):** https://github.com/esphome/feature-requests/issues/97

**Pull request in [esphome-docs](https://github.com/esphome/esphome-docs) with documentation (if applicable):** esphome/esphome-docs#<esphome-docs PR number goes here>

## Checklist:
  - [ ] The code change is tested and works locally.
  - [ ] Tests have been added to verify that the new code works (under `tests/` folder).

If user exposed functionality or configuration variables are added/changed:
  - [ ] Documentation added/updated in [esphomedocs](https://github.com/OttoWinter/esphomedocs).

esphome/components/api/__init__.py

@@ -0,0 +1,127 @@
+
+from esphome import automation
+from esphome.automation import ACTION_REGISTRY, CONDITION_REGISTRY, Condition
+import esphome.config_validation as cv
+import esphome.codegen as cg
+from esphome.const import CONF_DATA, CONF_DATA_TEMPLATE, CONF_ID, CONF_PASSWORD, CONF_PORT, \
+    CONF_REBOOT_TIMEOUT, CONF_SERVICE, CONF_VARIABLES, CONF_SERVICES, CONF_TRIGGER_ID
+from esphome.core import CORE, coroutine_with_priority
+
+api_ns = cg.esphome_ns.namespace('api')
+APIServer = api_ns.class_('APIServer', cg.Component, cg.Controller)
+HomeAssistantServiceCallAction = api_ns.class_('HomeAssistantServiceCallAction', cg.Action)
+KeyValuePair = api_ns.class_('KeyValuePair')
+TemplatableKeyValuePair = api_ns.class_('TemplatableKeyValuePair')
+APIConnectedCondition = api_ns.class_('APIConnectedCondition', Condition)
+
+UserService = api_ns.class_('UserService', cg.Trigger)
+ServiceTypeArgument = api_ns.class_('ServiceTypeArgument')
+ServiceArgType = api_ns.enum('ServiceArgType')
+SERVICE_ARG_TYPES = {
+    'bool': ServiceArgType.SERVICE_ARG_TYPE_BOOL,
+    'int': ServiceArgType.SERVICE_ARG_TYPE_INT,
+    'float': ServiceArgType.SERVICE_ARG_TYPE_FLOAT,
+    'string': ServiceArgType.SERVICE_ARG_TYPE_STRING,
+}
+SERVICE_ARG_NATIVE_TYPES = {
+    'bool': bool,
+    'int': cg.int32,
+    'float': float,
+    'string': cg.std_string,
+}
+
+
+CONFIG_SCHEMA = cv.Schema({
+    cv.GenerateID(): cv.declare_variable_id(APIServer),
+    cv.Optional(CONF_PORT, default=6053): cv.port,
+    cv.Optional(CONF_PASSWORD, default=''): cv.string_strict,
+    cv.Optional(CONF_REBOOT_TIMEOUT, default='5min'): cv.positive_time_period_milliseconds,
+    cv.Optional(CONF_SERVICES): automation.validate_automation({
+        cv.GenerateID(CONF_TRIGGER_ID): cv.declare_variable_id(UserService),
+        cv.Required(CONF_SERVICE): cv.valid_name,
+        cv.Optional(CONF_VARIABLES, default={}): cv.Schema({
+            cv.validate_id_name: cv.one_of(*SERVICE_ARG_TYPES, lower=True),
+        }),
+    }),
+}).extend(cv.COMPONENT_SCHEMA)
+
+
+@coroutine_with_priority(40.0)
+def to_code(config):
+    rhs = APIServer.new()
+    api = cg.Pvariable(config[CONF_ID], rhs)
+    yield cg.register_component(api, config)
+
+    cg.add(api.set_port(config[CONF_PORT]))
+    cg.add(api.set_password(config[CONF_PASSWORD]))
+    cg.add(api.set_reboot_timeout(config[CONF_REBOOT_TIMEOUT]))
+
+    for conf in config.get(CONF_SERVICES, []):
+        template_args = []
+        func_args = []
+        service_type_args = []
+        for name, var_ in conf[CONF_VARIABLES].items():
+            native = SERVICE_ARG_NATIVE_TYPES[var_]
+            template_args.append(native)
+            func_args.append((native, name))
+            service_type_args.append(ServiceTypeArgument(name, SERVICE_ARG_TYPES[var_]))
+        func = api.make_user_service_trigger.template(*template_args)
+        rhs = func(conf[CONF_SERVICE], service_type_args)
+        type_ = UserService.template(*template_args)
+        trigger = cg.Pvariable(conf[CONF_TRIGGER_ID], rhs, type=type_)
+        yield automation.build_automation(trigger, func_args, conf)
+
+    cg.add_define('USE_API')
+    if CORE.is_esp32:
+        cg.add_library('AsyncTCP', '1.0.3')
+    elif CORE.is_esp8266:
+        cg.add_library('ESPAsyncTCP', '1.2.0')
+
+
+CONF_HOMEASSISTANT_SERVICE = 'homeassistant.service'
+HOMEASSISTANT_SERVICE_ACTION_SCHEMA = cv.Schema({
+    cv.GenerateID(): cv.use_variable_id(APIServer),
+    cv.Required(CONF_SERVICE): cv.string,
+    cv.Optional(CONF_DATA): cv.Schema({
+        cv.string: cv.string,
+    }),
+    cv.Optional(CONF_DATA_TEMPLATE): cv.Schema({
+        cv.string: cv.string,
+    }),
+    cv.Optional(CONF_VARIABLES): cv.Schema({
+        cv.string: cv.lambda_,
+    }),
+})
+
+
+@ACTION_REGISTRY.register(CONF_HOMEASSISTANT_SERVICE, HOMEASSISTANT_SERVICE_ACTION_SCHEMA)
+def homeassistant_service_to_code(config, action_id, template_arg, args):
+    var = yield cg.get_variable(config[CONF_ID])
+    type = HomeAssistantServiceCallAction.template(template_arg)
+    rhs = type.new(var)
+    act = cg.Pvariable(action_id, rhs, type=type)
+    cg.add(act.set_service(config[CONF_SERVICE]))
+    if CONF_DATA in config:
+        datas = [KeyValuePair(k, v) for k, v in config[CONF_DATA].items()]
+        cg.add(act.set_data(datas))
+    if CONF_DATA_TEMPLATE in config:
+        datas = [KeyValuePair(k, v) for k, v in config[CONF_DATA_TEMPLATE].items()]
+        cg.add(act.set_data_template(datas))
+    if CONF_VARIABLES in config:
+        datas = []
+        for key, value in config[CONF_VARIABLES].items():
+            value_ = yield cg.process_lambda(value, [])
+            datas.append(TemplatableKeyValuePair(key, value_))
+        cg.add(act.set_variables(datas))
+    yield act
+
+
+CONF_API_CONNECTED = 'api.connected'
+API_CONNECTED_CONDITION_SCHEMA = cv.Schema({})
+
+
+@CONDITION_REGISTRY.register(CONF_API_CONNECTED, API_CONNECTED_CONDITION_SCHEMA)
+def api_connected_to_code(config, condition_id, template_arg, args):
+    rhs = APIConnectedCondition.new(template_arg)
+    type = APIConnectedCondition.template(template_arg)
+    yield cg.Pvariable(condition_id, rhs, type=type)