Throws exception when querying a removed vertex.
Fixed error message.
Made it mandatory for all storage backends to provide key consistency and removed TransactionalIDAuthority. Now, all stores use the KeyConsistentIDAuthority which allows operating transactional stores with disabled transactions without data corruption.
This refactoring effectively de-couples transactionality from the id allocation mechanism which makes it safer and the code easier.

Note, that this introduces an incompatibility with prior releases for the following backends:
BerkeleyDB, Persistit, and Hazelcast
because their id allocation mechanism has changed.

Hence, this branch should only be merged with the next MAJOR release branch.
Merge branch 'fixtx' into titan05

Conflicts:
	titan-berkeleyje/src/main/java/com/thinkaurelius/titan/diskstorage/berkeleyje/BerkeleyJEStoreManager.java
	titan-core/src/main/java/com/thinkaurelius/titan/diskstorage/Backend.java
	titan-core/src/main/java/com/thinkaurelius/titan/diskstorage/idmanagement/TransactionalIDManager.java
	titan-hazelcast/src/main/java/com/thinkaurelius/titan/diskstorage/hazelcast/AbstractHazelcastStoreManager.java
	titan-hbase/src/main/java/com/thinkaurelius/titan/diskstorage/hbase/HBaseStoreManager.java
	titan-infinispan/src/main/java/com/thinkaurelius/titan/diskstorage/infinispan/InfinispanCacheStoreManager.java
	titan-test/src/main/java/com/thinkaurelius/titan/diskstorage/LockKeyColumnValueStoreTest.java
	titan-test/src/main/java/com/thinkaurelius/titan/diskstorage/inmemory/InMemoryStorageAdapter.java
	titan-test/src/test/java/com/thinkaurelius/titan/graphdb/idmanagement/VertexIDAssignerTest.java
Fixed compilation issue after merge.