ESPixelStick v3.1 Firmware

This release wraps up the 3.1 development efforts. You can upgrade from 3.0 using the EFU files included in the release archive, however if you're on one of the newer Travis dev builds, it'll probably fail. This is due to changes that have occurred in the way SPIFFS (the internal file system we use) is handled by the Arduino ESP8266 core. This release also updates ESPSFlashTool to support the new ESPixelStick v3.0 hardware which is Wemos based. That means If you're on a NodeMCU or Wemos board, you no longer have to manually enter flash mode. Enjoy!