0.10.0: PMM-1011: Merge pull request #2 from percona/prometheus-master

Update with Upstream

v0.10.0 / 2017-04-25
BREAKING CHANGES:
mysql_slave_... metrics now include an additional connection_name label to support mariadb multi-source replication. (#178)

[FEATURE] Add read/write query response time #166
[FEATURE] Add Galera gcache size metric #169
[FEATURE] Add MariaDB multi source replication support #178
[FEATURE] Implement heartbeat metrics #183
[FEATURE] Add basic file_summary_by_instance metrics #189
[BUGFIX] Workaround MySQL bug 79533 #173