Add Atmel-ICE as AVR programmer

Author: facchinm

hardware/arduino/avr/programmers.txt

@@ -81,3 +81,9 @@ buspirate.program.protocol=buspirate
 buspirate.program.tool=avrdude
 buspirate.program.extra_params=-P{serial.port}
 
+atmel_ice.name=Atmel-ICE (AVR)
+atmel_ice.communication=usb
+atmel_ice.protocol=atmelice_isp
+atmel_ice.program.protocol=atmelice_isp
+atmel_ice.program.tool=avrdude
+atmel_ice.program.extra_params=-Pusb