Removed unused parameteri
It's now possible to specify additional custom board parameters when running the IDE from the command line
Eg: --board arduino:avr:pro:cpu=8MHzatmega168,other=value
Closes #1353
IDE command line: sketches can now be specified with relative paths. Fixes #1493
IDE Command line: using "isAbsolute" instead of "exists" to avoid conflicting with files in IDE install location