preTraverse()

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. Removed client.go and client_test.go
2. Modified protocol buffer structure to have Values as a struct which
contains byte slice.
3. Added support to calculate latency because of protocol buffer.

1. Protocol buffer now stores a entity based subgraph instead of a predicate
based subgraph.

HasValue and Value now look for value iteratively instead of storing it in a
map.

Removed Populate() method for entity. Now Properties() and Children() are
created during iteration.

Parsing and modifying the subgraph returned in the response. Provided helper
methods for the response.

Query would be needed to parse the Graph Response on the client side, hence
sending it in the protocol buffer response.

1. Added Values, HasValue and NumChildren functions

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