Some fixes for Arduino v1.0, new boards, pin variants, .ino file extensions

Stems from the original arscons at http://code.google.com/p/arscons/, but sadly this repository appears to have stagnated.
A copy was made at http://code.google.com/r/kylecgordon-arscons/, and subsequent changes applied from various contributors as in the change history. That repository has subsequently been migrated to Github.

* Tries to determine if you're using v1.0 or not. Uses original defaults if not

* Uses .ino file extension for v1.0+ sketches

* Includes relevant board variants if the appropriate ARDUINO_BOARD is specified

* Uses the new location of pins_arduino.h 

* Compresses the final .hex file

* Inclusion of .S files