Updates for Breakout Board Firmware version 2.0

[bparks13]

This is a meta issue to track the issues that will require version 2.0 of the breakout board firmware.

• Combine AnalogIO and DigitalIO into a single abstract device #42
• Polled Bno: Acceleration data shows jumps when centered around zero #49
• Events and ONI #30
• Add persistent heartbeat #79

[bparks13]

Increment the version check, so that the firmware is looking for version 2.x instead of 1.x

[bparks13]

Also requires a new version of liboni. We should also try to compile liboni as a static library.

Related to #19