🏗 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/partition/light.py

@@ -0,0 +1,36 @@
+import esphome.codegen as cg
+import esphome.config_validation as cv
+from esphome.components import light
+from esphome.const import CONF_FROM, CONF_ID, CONF_SEGMENTS, CONF_TO, CONF_OUTPUT_ID
+
+partitions_ns = cg.esphome_ns.namespace('partition')
+AddressableSegment = partitions_ns.class_('AddressableSegment')
+PartitionLightOutput = partitions_ns.class_('PartitionLightOutput', light.AddressableLight)
+
+
+def validate_from_to(value):
+    if value[CONF_FROM] > value[CONF_TO]:
+        raise cv.Invalid(u"From ({}) must not be larger than to ({})"
+                         u"".format(value[CONF_FROM], value[CONF_TO]))
+    return value
+
+
+CONFIG_SCHEMA = cv.nameable(light.ADDRESSABLE_LIGHT_SCHEMA.extend({
+    cv.GenerateID(CONF_OUTPUT_ID): cv.declare_variable_id(PartitionLightOutput),
+    cv.Required(CONF_SEGMENTS): cv.All(cv.ensure_list({
+        cv.Required(CONF_ID): cv.use_variable_id(light.AddressableLightState),
+        cv.Required(CONF_FROM): cv.positive_int,
+        cv.Required(CONF_TO): cv.positive_int,
+    }, validate_from_to), cv.Length(min=1)),
+}))
+
+
+def to_code(config):
+    segments = []
+    for conf in config[CONF_SEGMENTS]:
+        var = yield cg.get_variable(conf[CONF_ID])
+        segments.append(AddressableSegment(var, conf[CONF_FROM],
+                                           conf[CONF_TO] - conf[CONF_FROM] + 1))
+
+    var = cg.new_Pvariable(config[CONF_OUTPUT_ID], segments)
+    yield light.register_light(var, config)