Finished for real this time

Project is finished, last housecleaning pass for unnecessary bits and dead code.

Squashed the last bug (still moving cursor while in delete mode) by pulling out all logic from the joystick-polling task and putting it into the display task where it belongs.  Now uses events to hand over the button and joystick press information to other tasks.

Code should be well-commented.  Description of each major component, with helper functions explained and logic processes clarified.  Project overall purpose and function laid out in beginning.