🏗 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/cover/automation.h

@@ -0,0 +1,113 @@
+#pragma once
+
+#include "esphome/core/component.h"
+#include "esphome/core/automation.h"
+#include "cover.h"
+
+namespace esphome {
+namespace cover {
+
+template<typename... Ts> class OpenAction : public Action<Ts...> {
+ public:
+  explicit OpenAction(Cover *cover) : cover_(cover) {}
+
+  void play(Ts... x) override {
+    this->cover_->open();
+    this->play_next(x...);
+  }
+
+ protected:
+  Cover *cover_;
+};
+
+template<typename... Ts> class CloseAction : public Action<Ts...> {
+ public:
+  explicit CloseAction(Cover *cover) : cover_(cover) {}
+
+  void play(Ts... x) override {
+    this->cover_->close();
+    this->play_next(x...);
+  }
+
+ protected:
+  Cover *cover_;
+};
+
+template<typename... Ts> class StopAction : public Action<Ts...> {
+ public:
+  explicit StopAction(Cover *cover) : cover_(cover) {}
+
+  void play(Ts... x) override {
+    this->cover_->stop();
+    this->play_next(x...);
+  }
+
+ protected:
+  Cover *cover_;
+};
+
+template<typename... Ts> class ControlAction : public Action<Ts...> {
+ public:
+  explicit ControlAction(Cover *cover) : cover_(cover) {}
+
+  void play(Ts... x) override {
+    auto call = this->cover_->make_call();
+    if (this->stop_.has_value())
+      call.set_stop(this->stop_.value(x...));
+    if (this->position_.has_value())
+      call.set_position(this->position_.value(x...));
+    if (this->tilt_.has_value())
+      call.set_tilt(this->tilt_.value(x...));
+    call.perform();
+    this->play_next(x...);
+  }
+
+  TEMPLATABLE_VALUE(bool, stop)
+  TEMPLATABLE_VALUE(float, position)
+  TEMPLATABLE_VALUE(float, tilt)
+
+ protected:
+  Cover *cover_;
+};
+
+template<typename... Ts> class CoverPublishAction : public Action<Ts...> {
+ public:
+  CoverPublishAction(Cover *cover) : cover_(cover) {}
+  void play(Ts... x) override {
+    if (this->position_.has_value())
+      this->cover_->position = this->position_.value(x...);
+    if (this->tilt_.has_value())
+      this->cover_->tilt = this->tilt_.value(x...);
+    if (this->current_operation_.has_value())
+      this->cover_->current_operation = this->current_operation_.value(x...);
+    this->cover_->publish_state();
+    this->play_next(x...);
+  }
+
+  TEMPLATABLE_VALUE(float, position)
+  TEMPLATABLE_VALUE(float, tilt)
+  TEMPLATABLE_VALUE(CoverOperation, current_operation)
+
+ protected:
+  Cover *cover_;
+};
+
+template<typename... Ts> class CoverIsOpenCondition : public Condition<Ts...> {
+ public:
+  CoverIsOpenCondition(Cover *cover) : cover_(cover) {}
+  bool check(Ts... x) override { return this->cover_->is_fully_open(); }
+
+ protected:
+  Cover *cover_;
+};
+template<typename... Ts> class CoverIsClosedCondition : public Condition<Ts...> {
+ public:
+  CoverIsClosedCondition(Cover *cover) : cover_(cover) {}
+  bool check(Ts... x) override { return this->cover_->is_fully_closed(); }
+
+ protected:
+  Cover *cover_;
+};
+
+}  // namespace cover
+}  // namespace esphome