Enable third party contributions

- Add instructions for contributing to ARM Trusted Firmware.

- Update copyright text in all files to acknowledge contributors.

Change-Id: I9311aac81b00c6c167d2f8c889aea403b84450e5
diff --git a/lib/non-semihosting/strtol.c b/lib/non-semihosting/strtol.c
index 4a5a404..f743c41 100644
--- a/lib/non-semihosting/strtol.c
+++ b/lib/non-semihosting/strtol.c
@@ -33,9 +33,7 @@
  */
 
 /*
- * Portions copyright (c) 2009-2013, ARM Ltd. All rights reserved.
- * ---------------------------------------------------------------
- * File: lib/strtol.c
+ * Portions copyright (c) 2009-2013, ARM Limited and Contributors. All rights reserved.
  */
 
 #include "types.h"