Adding copyright to @matthijskooijman for the files he modified

Signed-off-by: Federico Fissore <f.fissore@arduino.cc>

Author: Federico Fissore

main.go

@@ -25,6 +25,7 @@
  * the GNU General Public License.
  *
  * Copyright 2015 Arduino LLC (http://www.arduino.cc/)
+ * Copyright 2015 Matthijs Kooijman
  */
 
 package main

src/arduino.cc/builder/constants/constants.go

@@ -25,6 +25,7 @@
  * the GNU General Public License.
  *
  * Copyright 2015 Arduino LLC (http://www.arduino.cc/)
+ * Copyright 2015 Matthijs Kooijman
  */
 
 package constants

src/arduino.cc/builder/sketch_source_merger.go

@@ -25,6 +25,7 @@
  * the GNU General Public License.
  *
  * Copyright 2015 Arduino LLC (http://www.arduino.cc/)
+ * Copyright 2015 Matthijs Kooijman
  */
 
 package builder

src/arduino.cc/builder/test/coan_runner_test.go

@@ -25,6 +25,7 @@
  * the GNU General Public License.
  *
  * Copyright 2015 Arduino LLC (http://www.arduino.cc/)
+ * Copyright 2015 Matthijs Kooijman
  */
 
 package test

src/arduino.cc/builder/test/helper.go

@@ -25,6 +25,7 @@
  * the GNU General Public License.
  *
  * Copyright 2015 Arduino LLC (http://www.arduino.cc/)
+ * Copyright 2015 Matthijs Kooijman
  */
 
 package test

src/arduino.cc/builder/test/prototypes_adder_test.go

@@ -25,6 +25,7 @@
  * the GNU General Public License.
  *
  * Copyright 2015 Arduino LLC (http://www.arduino.cc/)
+ * Copyright 2015 Matthijs Kooijman
  */
 
 package test

src/arduino.cc/builder/test/sketch_source_merger_test.go

@@ -25,6 +25,7 @@
  * the GNU General Public License.
  *
  * Copyright 2015 Arduino LLC (http://www.arduino.cc/)
+ * Copyright 2015 Matthijs Kooijman
  */
 
 package test