ENH: Able to run in continuous mode for long time frames (> 1hr) . Made decision to perform voltage conversion in the main thread to maintain connectivity with usb device. Included unit tests to verify that channels remain synchronized.
Merge branch 'testing' of https://github.com/accesio/AIOUSB into testing

Conflicts:
	AIOUSB/lib/AIOContinuousBuffer.c
	AIOUSB/lib/AIOContinuousBuffer.h
	AIOUSB/samples/USB-AI16-16/burst_test.c