add test for a peer that joins late
Use the store's revision at the time of clone start to request files (fixes #19)

This seems to fix the issue where we aren't able to add a new node by
connecting it to a node that wasn't the initial master node.
remove .tmp file laying around
make note of potential deadlock issues
Merge pull request #19 from mreiferson/issue_19

Fixes: A new Doozerd fails to join a cluster