Added mySmartUSB light ISP to programmers.txt

Rebase of arduino/Arduino#3252

Author: henningpohl

programmers.txt

@@ -104,3 +104,9 @@ atmel_ice.protocol=atmelice_isp
 atmel_ice.program.protocol=atmelice_isp
 atmel_ice.program.tool=avrdude
 atmel_ice.program.extra_params=-Pusb
+
+mySmartUSB_light.name=mySmartUSB light
+mySmartUSB_light.protocol=stk500v2
+mySmartUSB_light.communication=serial
+mySmartUSB_light.program.tool=avrdude
+mySmartUSB_light.program.extra_params=-P{serial.port}