Merge pull request #25 from stickbreaker/stickbreaker-Busy-Glitch

With this merge, `Wire()` can handle a bus fault, Grounding SDA and or SCL is now recoverable.

The signal glitch that was created when attaching pins to the i2c peripheral has now been solved!

A bus_busy status is now auto-magically cleared. When this status is detected upon entry into the hal layer i2cProcQueue(), i2cProcQueue() immediately returns I2C_ERROR_BUSY which cause TwoWire() to attempt to clear the bus, first is re-inits the i2c peripheral(hardware reset!), then it attempts to cycle the i2c bus manually. TwoWire() then retries the transaction once.

This branch should handle both I2C peripherals at the same time, UnTESTED, but, it should work.

Update Wire.h

Add define for library identification
#define STICKBREAKER // issue #17

Merge pull request #18 from rtwfroody/stickbreaker-cleanup

Fix compiler warning and an indent.
@rtwfroody looks good I'll merge it.