adds empty implementation of http peer
Send a RequestVoteMessage using json over http
Communicates with remote peer for append entries using json over http
ReceiveAppendEntries returns an error
Merge pull request #21 from wjdix/master

http peer, friend :shipit: :heart: :cake: #OH YEAH :koolaidman:
Voters update VotedFor on valid RequestVoteMessage.
Add HttpHandler POST /request_vote
Add HttpHandler POST /append_entries
New sets the new server's Id.
Candidates vote for themselves.
HTTP election integration test.
Fan out and retry append entries.