Refs #11: move common code of uuid to galerautils
Refs #15: measure message replication latency in evs input_map
Refs #15: add interface to expose gcomm stats to gcs
1. since evs_proto already measure replication message in validate_reg_msg, remove previous commit
2. put gcomm stats into NULL-terminated array. for simplicity, all stats are string.
3. rewrite galera stats_get returned buffer, to support variable stats vars
Merge branch 'msg-repl-latency' into yan
Merge branch 'uuid-refactor' into yan