links in README now point to discourse

Fix bugs: Set GRPC server in Goroutine. Break out of loop if ServeRequest returns error -- this was causing the 100% CPU usage issue.

Protobuffers

1. Port flag is now an integer. Client runs on port + 1
2. Made changes to README.md and testrun.sh to reflect this change.
3. Renamed variables

1. Renamed GetResponse to Query in DGraph service.
2. Client now accepts the ip of the server as a flag instead of just the port.
3. Removed ToProtocolBuffer method, and added PreTraverse as a method for a Subgraph.
4. Renamed runServerForClient to runGrpcServer.

Also query is now input as a flag in the client

Client now gets back protocol buffer data and is able to parse it into protocol buffer Subgraph

Don't log fatal on call to ServeTask. Just return error for that query.

Bug Fix: Parse RDFs with _uid_:0xid

Client establishes a TCP connection with server. Sends a sample query and parses response.
Server listens to client, handles the query and sends back response.

1. Added subgraph.proto file which has the message structure.
2. Added ToProtocolBuffer method which converts a subgraph to protocol buffer.

Change key formation, code to get list of predicates in a given store