main: add CORS support
Merge pull request #1013 from jonboulle/1013_cors

Add CORS support
store: fix recursive/dir arguments
Merge pull request #1132 from jonboulle/fix_store

store: fix recursive/dir arguments
etcdserver: init time.Time only if Expiration > 0

golang's concept of "zero" time does not align with the zero value of
a unix timestamp. Initializing time.Time with a unix timestamp of 0
makes time.Time.IsZero fail. Solve this by initializing time.Time only
if we care about the time.
Merge pull request #1131 from bcwaldon/1129

etcdserver: init time.Time only if Expiration > 0
etcdserver: correct X-Etcd-Index header

This adds an EtcdIndex field to store.Event and uses that as the header
instead of the node's modifiedIndex. To facilitate this in a non-racy
way, we set the EtcdIndex while holding the lock.