Resolve some warnings
Merge remote-tracking branch 'origin/master'

Conflicts:
	kernel/src/main/java/com/nanuvem/lom/kernel/Attribute.java
	kernel/src/main/java/com/nanuvem/lom/kernel/MetadataException.java
	kernel/src/test/java/com/nanuvem/lom/kernel/ClassServiceTest.java