Added support for SSD1306 over I2C

That silly i2c-dev.h header belongs at <linux/i2c-dev.h>, but two
different headers can be located there.  To avoid confusion and
simplify things, I'm just putting the version I need in libbone's
source and calling it a day.

Side note: libbone is being used in a serious project now.  Libbone
may end up being made better as a result.