Fix formatting and whitespace in Message.
Add more tests for the Message class.
Use correct imports for Maps and Lists.
Fix accidental imports of collection helper classes
Fix testGetStreamIds test.
Add more tests for Message.
Let getFields() return an ImmutableMap to avoid leaking mutable fields.
Create a copy of the fields because gelfj modifies them.

The issue has been reported to gelfj and is already fixed in the
upcoming gelfj release.
Empty/unset config values shouldn't be printed as "null"
Make Loggers static final where appropriate
Merge DeflectorSetupService and IndexerSetupService

If the IndexerSetupService hadn't been properly started before DeflectorSetupService
was run, the deflector just wouldn't be created on startup. By merging both services
we circumvent this specific race condition but there may some others be left.

Fixes #677
Upgrade to Jersey 2.11 and HK2 2.3.0-b10
Get rid of reflection-based monkey-patching of HK2

Instead of trying to override hard-coded defaults in the Injections class,
now the standard Java SPI (ServiceLoader) is being used. The required
Injector instance is created and held by the new GuiceInjectorHolder class
and used by Graylog2ServiceLocatorGenerator.