Pebble Steel SmartWatch Firmware 2.7

Changes for Firmware:

- Add Wakeup API
- Add launch_reason API
- Fix a bug that caused watch_info_get_color to crash the app when used
- Add clock_to_timestamp API
- Add clock_is_timezone_set API. In firmware 2.7, this function will always return false as timezone support is not yet implemented
- Improve Bluetooth reliability
- Fix bug showing 0% battery warning
- Add wakeup example