update SAM core to 1.6.8

Author: facchinm

hardware/arduino/sam/platform.txt

@@ -6,7 +6,7 @@
 # https://github.com/arduino/Arduino/wiki/Arduino-IDE-1.5-3rd-party-Hardware-specification
 
 name=Arduino ARM (32-bits) Boards
-version=1.6.7
+version=1.6.8
 
 # SAM3 compile variables
 # ----------------------
@@ -105,4 +105,4 @@ tools.bossac.upload.params.quiet=
 tools.bossac.upload.params.verify=-v
 tools.bossac.upload.pattern="{path}/{cmd}" {upload.verbose} --port={serial.port.file} -U {upload.native_usb} -e -w {upload.verify} -b "{build.path}/{build.project_name}.bin" -R
 
-tools.bossac_remote.upload.pattern=/usr/bin/run-bossac {upload.verbose} --port=ttyATH0 -U {upload.native_usb} -e -w -v -b /tmp/sketch.bin -R
+tools.bossac_remote.upload.pattern=/usr/bin/run-bossac {upload.verbose} --port=ttyATH0 -U {upload.native_usb} -e -w -v -b /tmp/sketch.bin -R