🏗 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/rc5_protocol.cpp

@@ -0,0 +1,62 @@
+#include "rc5_protocol.h"
+#include "esphome/core/log.h"
+
+namespace esphome {
+namespace remote_base {
+
+static const char *TAG = "remote.rc5";
+
+static const uint32_t BIT_TIME_US = 889;
+static const uint8_t NBITS = 14;
+
+void RC5Protocol::encode(RemoteTransmitData *dst, const RC5Data &data) {
+  static bool TOGGLE = false;
+  dst->set_carrier_frequency(36000);
+
+  uint64_t out_data = 0;
+  out_data |= 0b11 << 12;
+  out_data |= TOGGLE << 11;
+  out_data |= data.address << 6;
+  out_data |= data.command;
+
+  for (uint64_t mask = 1UL << (NBITS - 1); mask != 0; mask >>= 1) {
+    if (out_data & mask) {
+      dst->space(BIT_TIME_US);
+      dst->mark(BIT_TIME_US);
+    } else {
+      dst->mark(BIT_TIME_US);
+      dst->space(BIT_TIME_US);
+    }
+  }
+  TOGGLE = !TOGGLE;
+}
+optional<RC5Data> RC5Protocol::decode(RemoteReceiveData src) {
+  RC5Data out{
+      .address = 0,
+      .command = 0,
+  };
+  src.expect_space(BIT_TIME_US);
+  if (!src.expect_mark(BIT_TIME_US) || !src.expect_space(BIT_TIME_US) || !src.expect_mark(BIT_TIME_US))
+    return {};
+
+  uint64_t out_data = 0;
+  for (int bit = NBITS - 3; bit >= 0; bit--) {
+    if (src.expect_space(BIT_TIME_US) && src.expect_mark(BIT_TIME_US)) {
+      out_data |= 1 << bit;
+    } else if (src.expect_mark(BIT_TIME_US) && src.expect_space(BIT_TIME_US)) {
+      out_data |= 0 << bit;
+    } else {
+      return {};
+    }
+  }
+
+  out.command = out_data & 0x3F;
+  out.address = (out_data >> 6) & 0x1F;
+  return out;
+}
+void RC5Protocol::dump(const RC5Data &data) {
+  ESP_LOGD(TAG, "Received RC5: address=0x%02X, command=0x%02X", data.address, data.command);
+}
+
+}  // namespace remote_base
+}  // namespace esphome