build.xml: added ARM arch, removed other OS
dir_struct: Removed other OS build dirs
dir_struct: removed AVR tools

Conflicts:
	hardware/arduino/avr/boards.txt
	hardware/arduino/avr/cores/arduino/Arduino.h
	hardware/arduino/avr/variants/leonardo/pins_arduino.h
	hardware/arduino/avr/variants/mega/pins_arduino.h
	hardware/arduino/avr/variants/robot_control/pins_arduino.h
	hardware/arduino/avr/variants/robot_motor/pins_arduino.h
	hardware/arduino/avr/variants/standard/pins_arduino.h
	hardware/arduino/avr/variants/yun/pins_arduino.h
removed ADK and AVR binary tools
added ARM precompiled BOSSAC
sam/platform.txt: modified for compiled custom path
Added arm-none-eabi ARM cross-compiler
Removed AVR header file