Port Phoenix to Hbase96

1) Change POM to use hbase96 binary
2) Add ProtoBuffer support(you need to install ProtoBuffer2.5 locally to generate PB java files from src/main/protobuf/*.proto)
3) Migrate End-Point coprocessor to HBase 96 style
4) Wrap filter into PB Writables in order for them to be RPCed
5) Change KeyValue to Cell in all needed places