Prerelease of Version 2.0

Installation instructions available at https://github.com/deckerego/hack-clock/blob/master/README.md

This is the almost-final release Hack Clock v2. It now fully supports:

• I2C audio
• Raspberry Pi Zero support
• Programming by block (using Blockly)
• Multiple simultaneous buttons (input pins)
• Support for switches (output pins)
• Debian packaging for ease of installation