Orient like modules

Created maven modules like in orientdb-project.
+ **network-proto** - protocol definition. Configured maven-protoc-plugin to generate and publish Java generated code.
+ **protobuf-protocol** - for new server network protocol. Copied current binary protocol implementation for further modification.
+ **protobuf-client** - for new java client

Changed output directory to _target_ which is more in maven style.

Field _"class"_ renamed to _"oclass"_. Fields with name _"class"_ is not valid for java, because protoc generates getClass method that is alredy defined in `java.lang.Object`