Parse method to get counter metadata, continued tests
convenience methos to get current week or year counters
Introduce Exceptions and better response codes
Merge branch 'feature-agatteExceptions' into feature-weekcounter

Conflicts:
	AgatteClient/src/main/java/com/agatteclient/agatte/AgatteParser.java
fix some bugs about newer AgatteResponse implementation
Parse counter value
More Parser tests