Imports of package api

PathSynopsis
github.com/coreos/etcd/etcdserver/membership
github.com/coreos/etcd/pkg/typesPackage types declares various data types and implements type-checking functions.
github.com/coreos/etcd/versionPackage version implements etcd version parsing and contains latest version information.
github.com/coreos/go-semver/semverSemantic Versions http://semver.org
github.com/coreos/pkg/capnslog
syncPackage sync provides basic synchronization primitives such as mutual exclusion locks.