Merge pull request #78 from bonifaido/master

AsyncWriteEngine.commit() hangs when writerThread dies
Add ignored test
Rework Volumes. Add compile time dependency on JDK7. But it should still run with JDK6
Fox possible locking problem
Merge pull request #83 from bonifaido/master

Fixing Queue.clear() method
Fix DeadLock in loading the SerializerBase Class, Issue #84

Credit goes to Patrice Freydiere
Fix Issue #77, errors in StorageAppend
Fixed Issue #82, Commit with async write hangs when POJOs are used.
Improve concurrency in StorageAppend engine
Concurrency in Storages, StorageAppend defrag.
Update README.md