Setup pins, setup timer, shrink code size (static declarations), test

Setup pins, setup timer, shrink code size (static declarations), test

This commit sets up all the appropriate I/O for the AVR as well as
declaring some functions static so GCC will inline them.  In addition,
it provides a simple test function to see if the USB HID reports are
being sent correctly - every 60 reports, it adds one to the report that
it returns, which should result in a binary "counting" appearance in a
gamepad state viewer.