🏗 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/fastled_base/fastled_light.cpp

@@ -0,0 +1,61 @@
+#include "fastled_light.h"
+#include "esphome/core/log.h"
+
+namespace esphome {
+namespace fastled_base {
+
+static const char *TAG = "fastled";
+
+void FastLEDLightOutput::setup() {
+  ESP_LOGCONFIG(TAG, "Setting up FastLED light...");
+  this->controller_->init();
+  this->controller_->setLeds(this->leds_, this->num_leds_);
+  this->effect_data_ = new uint8_t[this->num_leds_];
+  if (!this->max_refresh_rate_.has_value()) {
+    this->set_max_refresh_rate(this->controller_->getMaxRefreshRate());
+  }
+}
+void FastLEDLightOutput::dump_config() {
+  ESP_LOGCONFIG(TAG, "FastLED light:");
+  ESP_LOGCONFIG(TAG, "  Num LEDs: %u", this->num_leds_);
+  ESP_LOGCONFIG(TAG, "  Max refresh rate: %u", *this->max_refresh_rate_);
+}
+void FastLEDLightOutput::loop() {
+  if (!this->should_show_())
+    return;
+
+  uint32_t now = micros();
+  // protect from refreshing too often
+  if (*this->max_refresh_rate_ != 0 && (now - this->last_refresh_) < *this->max_refresh_rate_) {
+    return;
+  }
+  this->last_refresh_ = now;
+  this->mark_shown_();
+
+  ESP_LOGVV(TAG, "Writing RGB values to bus...");
+
+#ifdef USE_POWER_SUPPLY
+  if (this->power_supply_ != nullptr) {
+    bool is_on = false;
+    for (int i = 0; i < this->num_leds_; i++) {
+      if (bool(this->leds_[i])) {
+        is_on = true;
+        break;
+      }
+    }
+
+    if (is_on && !this->has_requested_high_power_) {
+      this->power_supply_->request_high_power();
+      this->has_requested_high_power_ = true;
+    }
+    if (!is_on && this->has_requested_high_power_) {
+      this->power_supply_->unrequest_high_power();
+      this->has_requested_high_power_ = false;
+    }
+  }
+#endif
+  this->controller_->showLeds();
+}
+
+}  // namespace fastled_base
+}  // namespace esphome