First cut at beaglebone implementation.  Works.
Clean up chunking code and samples.
Updated comments for BBB branch.
ported to bbb GPIO calls
Added abstraction layer to hide RPi/BBB differences.
spi and gpio abstraction layer working for bbb and rpi enough to run ssd1306_sample.py.
rotary encoder logic updated to use abstraction layer
converted to use gpio abstraction.
Change platform detection method and expose it in library
Updated capswitch sample for multi-platform
Updated rgbled for multi-platform
updated for multi-platform
add GPIO initialization
Updated for multi-platform (but only runs on rpi)
updated to multi-platform