🏗 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/image/__init__.py

@@ -0,0 +1,57 @@
+# coding=utf-8
+import logging
+
+from esphome import core
+from esphome.components import display, font
+import esphome.config_validation as cv
+import esphome.codegen as cg
+from esphome.const import CONF_FILE, CONF_ID, CONF_RESIZE
+from esphome.core import CORE, HexInt
+_LOGGER = logging.getLogger(__name__)
+
+DEPENDENCIES = ['display']
+MULTI_CONF = True
+
+Image_ = display.display_ns.class_('Image')
+
+CONF_RAW_DATA_ID = 'raw_data_id'
+
+IMAGE_SCHEMA = cv.Schema({
+    cv.Required(CONF_ID): cv.declare_variable_id(Image_),
+    cv.Required(CONF_FILE): cv.file_,
+    cv.Optional(CONF_RESIZE): cv.dimensions,
+    cv.GenerateID(CONF_RAW_DATA_ID): cv.declare_variable_id(cg.uint8),
+})
+
+CONFIG_SCHEMA = cv.All(font.validate_pillow_installed, IMAGE_SCHEMA)
+
+
+def to_code(config):
+    from PIL import Image
+
+    path = CORE.relative_path(config[CONF_FILE])
+    try:
+        image = Image.open(path)
+    except Exception as e:
+        raise core.EsphomeError(u"Could not load image file {}: {}".format(path, e))
+
+    if CONF_RESIZE in config:
+        image.thumbnail(config[CONF_RESIZE])
+
+    image = image.convert('1', dither=Image.NONE)
+    width, height = image.size
+    if width > 500 or height > 500:
+        _LOGGER.warning("The image you requested is very big. Please consider using the resize "
+                        "parameter")
+    width8 = ((width + 7) // 8) * 8
+    data = [0 for _ in range(height * width8 // 8)]
+    for y in range(height):
+        for x in range(width):
+            if image.getpixel((x, y)):
+                continue
+            pos = x + y * width8
+            data[pos // 8] |= 0x80 >> (pos % 8)
+
+    rhs = [HexInt(x) for x in data]
+    prog_arr = cg.progmem_array(config[CONF_RAW_DATA_ID], rhs)
+    cg.new_Pvariable(config[CONF_ID], prog_arr, width, height)