🏗 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/esp32_touch/binary_sensor.py

@@ -0,0 +1,50 @@
+import esphome.codegen as cg
+import esphome.config_validation as cv
+from esphome.components import binary_sensor
+from esphome.components.esp32_touch import ESP32TouchComponent
+from esphome.const import CONF_NAME, CONF_PIN, CONF_THRESHOLD, ESP_PLATFORM_ESP32, CONF_ID
+from esphome.pins import validate_gpio_pin
+from . import esp32_touch_ns
+
+ESP_PLATFORMS = [ESP_PLATFORM_ESP32]
+DEPENDENCIES = ['esp32_touch']
+
+CONF_ESP32_TOUCH_ID = 'esp32_touch_id'
+
+TOUCH_PADS = {
+    4: cg.global_ns.TOUCH_PAD_NUM0,
+    0: cg.global_ns.TOUCH_PAD_NUM1,
+    2: cg.global_ns.TOUCH_PAD_NUM2,
+    15: cg.global_ns.TOUCH_PAD_NUM3,
+    13: cg.global_ns.TOUCH_PAD_NUM4,
+    12: cg.global_ns.TOUCH_PAD_NUM5,
+    14: cg.global_ns.TOUCH_PAD_NUM6,
+    27: cg.global_ns.TOUCH_PAD_NUM7,
+    33: cg.global_ns.TOUCH_PAD_NUM8,
+    32: cg.global_ns.TOUCH_PAD_NUM9,
+}
+
+
+def validate_touch_pad(value):
+    value = validate_gpio_pin(value)
+    if value not in TOUCH_PADS:
+        raise cv.Invalid("Pin {} does not support touch pads.".format(value))
+    return value
+
+
+ESP32TouchBinarySensor = esp32_touch_ns.class_('ESP32TouchBinarySensor', binary_sensor.BinarySensor)
+
+CONFIG_SCHEMA = cv.nameable(binary_sensor.BINARY_SENSOR_SCHEMA.extend({
+    cv.GenerateID(): cv.declare_variable_id(ESP32TouchBinarySensor),
+    cv.GenerateID(CONF_ESP32_TOUCH_ID): cv.use_variable_id(ESP32TouchComponent),
+    cv.Required(CONF_PIN): validate_touch_pad,
+    cv.Required(CONF_THRESHOLD): cv.uint16_t,
+}))
+
+
+def to_code(config):
+    hub = yield cg.get_variable(config[CONF_ESP32_TOUCH_ID])
+    var = cg.new_Pvariable(config[CONF_ID], config[CONF_NAME], TOUCH_PADS[config[CONF_PIN]],
+                           config[CONF_THRESHOLD])
+    yield binary_sensor.register_binary_sensor(var, config)
+    cg.add(hub.register_touch_pad(var))