Fix issue #522
Improvements suggested by @garcia-jj and @lucascs
Add test to check if deserialization is honoring Accept-Charset header
Fix encoding problem on source file
Add test to check behavior when no Charset Header is found
Merge remote-tracking branch 'marceloemanoel/master'

Conflicts:
	vraptor-core/src/main/java/br/com/caelum/vraptor/deserialization/gson/GsonDeserialization.java
	vraptor-core/src/test/java/br/com/caelum/vraptor/deserialization/gson/GsonDeserializerTest.java