Various cleanups and warning fixes.

Particularly interesting is the change to ZooKeeperUpdatingPersistentDirectory.
I have no idea if that ever worked, as if it ever removed a node, it would get
a ConcurrentModificationException.
Reset joda-time to use system clock after test.

This would actually have a chance to affect other tests later on,
e.g. the ExpiredJobReaperTest which also depends on now()
Merge pull request #212 from mbruggmann/fix-now-in-grace-test

Reset joda-time to use system clock after test.
Add failing test case for container termination
Stop containers instead of killing them.
Only run the TerminationTest if docker runs the native driver.
Merge pull request #207 from dflemstr/termination

Stop running containers instead of killing them on undeploy
Merge pull request #211 from spotify/drewc/cleanups

Various cleanups and warning fixes.
Remove some system time dependencies

Either remove the use of the clock altogether where it was
unnecessary, or refactor things to use a Clock interface
for controlling time.
Merge pull request #213 from spotify/drewc/useclock

Remove some system time dependencies
Remove more leftover clock manipulation in test.
Merge pull request #214 from mbruggmann/remove-leftover-clock-manipulation

Remove leftover clock manipulation in test.
[maven-release-plugin] prepare release 0.8.20
[maven-release-plugin] prepare for next development iteration
Fix imports and pom.xml files
Interesting parts of conversion to Dropwizard 7
Conversion to codahale metrics from yammer
Rename banner.txt so Dropwizard 7 doesn't print it twice.

Now it gets printed manually in logBanner, which was always there.
This change just works around Dropwizard's auto-banner.txt printing.