Add mysql slow query log filter
Added spec
Test multilne and buffer size restriction
Add mysql_slow entry3
Drop in a mysql-slow-query log filter that also adds the query fingerprint to the log.
Comment out the test that pt-fingerprint doesn't handle.
It's ok to lose some precision in the payload
Fix multiple glob test on Linux.

If you have 2 sinks looking at the same log file then
events can be sent to the wrong one.
Fix sparodically failing test due to iso8601 truncating rather than
rounding
Merge branch 'test-fixes' into mysql-slow-query-logs

Conflicts:
	spec/unit/event_spec.rb