Removed the unnecessary extract function and result struct. Now preTraverse
directly acceses flatbuffers to get values and uidmatrix.
Renamed struct fields in the protocol buffer schema file.

1. Added Values, HasValue and NumChildren functions

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

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.