feat add dir_flag
refactor(update) more clear dir checking
tests fix all tests
refactor(error.go) error messages
docs(delete_command.go) document about recursive implies dir
test fix tests
tests add tests for dir flag
refactor remove unused const
Refactor mod/lock.
doc fix grammar issue
Merge pull request #376 from xiangli-cmu/dir_flag

feat add dir_flag
hack(travis): temporarily fix travis

try a quick workaround for https://github.com/travis-ci/travis-ci/issues/1727
chore(server): cleanup some whitespace
fix(store.go) expire should also notify all the watchers under the path
Merge https://github.com/coreos/etcd into fix_expire_notify
fix(server): try and add a expire dir test

This doesn't actually work yet.
Merge branch 'add-expire-dir-test' of https://github.com/philips/etcd into fix_expire_notify
fix TestV2WatchKeyInDir test
Merge pull request #387 from xiangli-cmu/fix_expire_notify

Fix expire notify
fix index inconsistence in v1 api