ez-clang-0.0.6

Apart form maintenance changes and cleanup this release extends the reference implementations for two ARMv6-based boards:

• TeensyLC: 62k Flash, 8k RAM, 48 MHz Cortex-M0+
  https://www.pjrc.com/teensy/teensyLC.html
• Adafruit Metro M0: 256k Flash, 32k RAM, 48 MHz Cortex-M0+(ATSAMD21G18)
  https://www.adafruit.com/product/3505

These firmware are supposed to work with ez-clang release versions 0.0.5 and 0.0.6 as the RPC protocol has not changed (yet). However, the handshake step was extended to send the magic sequence both ways before starting the REPL session.