Several new features and improvements

1. Moved strings to program memory to reduce RAM usage
2. Added "pin sweep" function to help "find" pins
3. Added "clock" function to strobe any pin off and on continuously
(with a given delay)
4. Set EEPROM settings to be stored from the top of EEPROM memory space
so that the sketch can be used on boards with other sketches and not
conflict.
5. Added warning that a pin is not set to output mode for output
functions