Merge pull request #1 from wjdix/master

adds LogEntry type and derives lastLogTerm based on it
Merge pull request #2 from wjdix/master

Adds step down behavior when receiving appendEntries. Also, go fmt
Merge pull request #3 from wjdix/master

Additional failure/success cases for appendEntries rpc
Voters will not grant a vote to a canidate with an out of date log.
Merge pull request #4 from benmills/master

Voters will not grant a vote to a canidate with an out of date log.
Add ElectionTimer.