Add BLE transport

[soundanalogous]

The Arduino 101 has BLE. Add the ability to use BLE as a transport (so a user can communicate with the board using Firmata over BLE).

This will be challenging due to the limited size of data packets (20 bytes per packet and up to 6 packets per interval). Could use some help with this if there are any BLE experts who would like to see this functionality added to Firmata.

[soundanalogous]

Work in progress: https://github.com/firmata/arduino/tree/ble

[soundanalogous]

Further progress for Arduino 101 BLE is currently blocked by: arduino/ArduinoCore-arc32#95

[soundanalogous]

The work for this is mostly done. Will be merged into master once the Arduino 101 core v1.0.5 update is released and updatable via the Arduino Boards Manager.

[soundanalogous]

Merged. However, setConnectionInterval is skipped for Arduino 101 by default. Should be available without patching when Intel releases the Curie Board v1.0.6 package. Until then CurieBLE can be patched which will result in a much better reporting interval for analog input and I2C continuous reads.