Update copyright
Gather lock counts for the current db

Tag with lock mode and table name (though indices will show up here
as well).
Add tests for jenkins agent check
Fix jenkins agent check when build does not yet have results
Refactor jenkins agent tests
Add build result as a tag to jenkins events
Add build number to tags for jenkins results
add logging of serverStatus errors

The current code does not check if db.serverStatus() returns an error (e.g. insufficient privileges). If that is the case, no message is logged anywhere, so user has no clue why metrics are not being posted. I propose to log a warning with the error message.
That host header is et by the collector to localhost:17123

Some proxies will use that header upon CONNECT request and will make
the forwarder to repoint the trafic to the localhost (e.g. blue coat
proxies).
Add bgwriter stats
Merge from master

Conflicts:
	checks.d/postgres.py
Add a test for bgwriter and lock collection
Merge pull request #1068 from jzoldak/jenkins-add-result-tag

Add result and build number to tags for jenkins events
Merge pull request #1065 from igroenewold/patch-1

add logging of serverStatus errors
Raise an exception instead so the execution stops and error appears in the info page
Update tests with new bgwriter stats.

Locks require scaffolding to test. May consider afterwards
Merge pull request #1019 from DataDog/alq/pg-locks

Postgres locks per mode and thing locked
Catch exceptions and restart
Track table/index size
Add simple tests for table/index sizes