A bunch of new MySQL global status tracking plugins.

This commit adds 6 new MySQL plugins that track a number of additional
values that MySQL reports in global status.

Buffer pool stats: tracks operations on the buffer pool, as well as its
                   current size.
Data/Log stats: Tracks data & log operations (reads, writes, bytes
                read/written, etc)
Extra stats: Miscellaneous stats
Handler stats: Tracks operations on MySQL's handler layer
Innodb rows stats: Stats about InnoDB's operations at a row level
Sort/Select: Tracks sort & select type counts
Detect if zookeeper isn't serving requests
Make sure we return all fields that are possible
Send up metric
Merge pull request #90 from eric/zookeeper-check-for-errors

Detect if zookeeper isn't serving requests
Fixing typo
added passenger 4 support
Merge branch 'master' of github.com:scoutapp/scout-plugins
Better ntpstat data
added an optional parameter to specify the path for varnishstat if it is not on the default path.
changed counter granularity to seconds as the metrics from varnishstat are per second
Merge pull request #62 from dougbarth/additional_mysql_plugins

A bunch of new MySQL global status tracking plugins.
Use the original key for synchronized in ntpstat
Merge pull request #91 from yardstick/better-ntpstat

Better ntpstat data - added accuracy, polling, and labels.
Add ceph plugin.
Add ceph.yml
Don't send string values.
Oops, left some debug code in there.
More tweaking of ceph.yml
Add trigger for ceph health