Add usb_midi_class::setHandleSysEx()

Switched order of parameters as suggested by PaulStoffregen.

more 2 MHz (VLPR) fixes

resync

fix for 2 and 4MHz

resync

resync

resync

configurable path to toolchain

Use the proper way to refer to gcc's asm extension so we can compile this in C standard mode.

added gitignore file to ignore compile results

+Overclock 144 MHz only

Attention, slower SPI

thank you, duff !

http://forum.pjrc.com/threads/25494-Problems-with-HardwareSerial-Pointer-and-write

http://forum.pjrc.com/threads/25482-Duplicate-usb-modem-number-HELP!