Add license checking (#1353)

It's stated in the Guidelines that all contributions must be under
the Apache License 2.0. To avoid potential mistakes from manual
reviews, this patch adds the check-license.py script to
automatically check all source files for license headers.

Travis CI is also configured to run the check.

Fallout: it turned out that some files already in the code base
either miss a license header or have some minor typo differences.
The patch fixes up some of these deficiences.

JerryScript-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu

tools/run-tests.py

@@ -31,6 +31,7 @@ parser.add_argument('--check-signed-off-tolerant', action='store_true', default=
 parser.add_argument('--check-signed-off-travis', action='store_true', default=False, help='Run signed-off check in tolerant mode if on Travis CI and not checking a pull request')
 parser.add_argument('--check-cppcheck', action='store_true', default=False, help='Run cppcheck')
 parser.add_argument('--check-vera', action='store_true', default=False, help='Run vera check')
+parser.add_argument('--check-license', action='store_true', default=False, help='Run license check')
 parser.add_argument('--buildoption-test', action='store_true', default=False, help='Run buildoption-test')
 parser.add_argument('--jerry-tests', action='store_true', default=False, help='Run jerry-tests')
 parser.add_argument('--jerry-test-suite', action='store_true', default=False, help='Run jerry-test-suite')
@@ -197,6 +198,9 @@ def main():
     if not ret and (script_args.all or script_args.check_vera):
         ret = run_check(VERA_SCRIPT)
 
+    if not ret and (script_args.all or script_args.check_license):
+        ret = run_check(LICENSE_SCRIPT)
+
     if not ret and (script_args.all or script_args.jerry_tests):
         ret = run_jerry_tests()