Misc ioHub stuff

ENH - Updated SMI SDK version supported
BF - eye_tracker demo no longer requires xlrd
ENH - EyeTribe data is now streaming / saved to data store
ADD - initial commit for Teensy 3 MCU support for 8 digitial input /  8 output , 8 analog input. MCU connected to psychopy PC using USB cable.
ENH - LabJack analog input device now supports setting a time offset to apply to analog input sample times to correct for time difference between when device is asked to start streaming and when the device actually starts streaming samples. Error seems to usually be between 15 - 30 msec. Is consistent for a given labjack / computer setup but varies across installations.