add logging and backoff and simple retry logic
Add *.test to gitignore.

These files are left by some go commands.
Raft: fix problems reported by golint.
Raft: fix printf strings found by go vet.
raft: remove misleading labels in array definition

Since these are arrays instead of maps, the "keys" here are actually
(useless) goto labels. What really matters is that the ordering is
the same between the constant declarations and the array.
fix retry to not retry on createSelf()
raft: save removed nodes in snapshot
Raft: a few more improvements to test messages.
Merge pull request #1257 from bdarnell/cleanups

Raft: assorted cleanups (golint and go vet)
raft: removedSlice -> removedNodes
raft: more comment
etcdserver: add discovery warning message
Merge pull request #1269 from jonboulle/disco_warn

etcdserver: add discovery warning message
test retry logic
Merge pull request #1260 from coreos/snap_rm

raft: save removed nodes in snapshot
simplify and multiple retry
add too many retries test case
raft: int64 -> uint64
*: raft related int64 -> uint64
raft: fix raft test