🏗 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/remote_base/remote_base.cpp

@@ -0,0 +1,59 @@
+#include "remote_base.h"
+#include "esphome/core/log.h"
+
+namespace esphome {
+namespace remote_base {
+
+static const char *TAG = "remote_base";
+
+RemoteComponentBase::RemoteComponentBase(GPIOPin *pin) : pin_(pin) {
+#ifdef ARDUINO_ARCH_ESP32
+  static rmt_channel_t next_rmt_channel = RMT_CHANNEL_0;
+  this->channel_ = next_rmt_channel;
+  next_rmt_channel = rmt_channel_t(int(next_rmt_channel) + 1);
+#endif
+}
+
+void RemoteReceiverBinarySensorBase::dump_config() { LOG_BINARY_SENSOR("", "Remote Receiver Binary Sensor", this); }
+
+void RemoteTransmitterBase::send_(uint32_t send_times, uint32_t send_wait) {
+#ifdef ESPHOME_LOG_HAS_VERY_VERBOSE
+  const std::vector<int32_t> &vec = this->temp_.get_data();
+  char buffer[256];
+  uint32_t buffer_offset = 0;
+  buffer_offset += sprintf(buffer, "Sending times=%u wait=%ums: ", send_times, send_wait);
+
+  for (int32_t i = 0; i < vec.size(); i++) {
+    const int32_t value = vec[i];
+    const uint32_t remaining_length = sizeof(buffer) - buffer_offset;
+    int written;
+
+    if (i + 1 < vec.size()) {
+      written = snprintf(buffer + buffer_offset, remaining_length, "%d, ", value);
+    } else {
+      written = snprintf(buffer + buffer_offset, remaining_length, "%d", value);
+    }
+
+    if (written < 0 || written >= int(remaining_length)) {
+      // write failed, flush...
+      buffer[buffer_offset] = '\0';
+      ESP_LOGVV(TAG, "%s", buffer);
+      buffer_offset = 0;
+      written = sprintf(buffer, "  ");
+      if (i + 1 < vec.size()) {
+        written += sprintf(buffer + written, "%d, ", value);
+      } else {
+        written += sprintf(buffer + written, "%d", value);
+      }
+    }
+
+    buffer_offset += written;
+  }
+  if (buffer_offset != 0) {
+    ESP_LOGVV(TAG, "%s", buffer);
+  }
+#endif
+  this->send_internal(send_times, send_wait);
+}
+}  // namespace remote_base
+}  // namespace esphome