Utility for checking the encoding and line ending of source files (#5188)

* Add utility for checking the encoding of source files

- accept source files with ASCII or UTF-8 without BOM
- accept only CRLF line ending

* Fix non-ascii symbol in idl_parcer.cpp

* Remove BOM from test.cpp

tests/test.cpp

@@ -1,4 +1,4 @@
-/*
+/*
  * Copyright 2014 Google Inc. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");