Introduced alternate model of key eventing, to permit redirection in the future where people want different triggers (e.g. bypassing UsbKeyboard.h) and also to permit keyup and keydown events to be distinct (simultaneous keystrokes). Fixed PROGMEM declarations with const to satisfy new Arduino compilation rules.
Fixed PROGMEM declarations with const to satisfy new Arduino compilation rules.
Changed pins to free up pin 3 (an interrupt pin), and assign the control pin to 5 (e.g. more convenient for layout - a single run of buttons from pins 6-8 on portD, and fewer chances for shorts).
Introduced simplified default keymappings (based on Hex) - probably A-F would preferably be keycodes like space etc. when we've added them. Added also a simplified test case, which should perhaps be configured by default, so that testing is simplified and users are required to author a list of keys to get more than one. Note, the center value has been moved from MakeyMakey's 70 to ShrimpKey's 55, but this value should be verified (and possibly differentiated) for both copper and breadboard.
Changed settings to correspond with only 4 key assignments
Determined 14 inputs (to exclude usb control and led flasher). Added testing configuration commented (a single pin).
Removed spurious duplicate library includes. 
Comment to include additional authorship and link to vusb-for-arduino.
Removed extra unnecessary key state flags.
Removed LED control logic with the idea of reimplementing a new behaviour on one LED (Pin 13)
Removed spurious DEBUG* defines and simplified DEBUG logic
Added fix for latent bug in MakeyMakey around loop timing overflow on int. Introduced usb update as the heartbeat in the delay loop to ensure USB timing is serviced as often as possible.
Changed to leave only one pin active for testing.
Merge pull request #22 from cefn/master

Merging Cefn's changes