Introduce Guice to the game.

This removes the need to have a Map keeping the different pools available. This also means that the pools are singleton, living for the life of the application. As such, they are not unregistered from the PlatformMBeanServer, they will disapear with the application by themselves.
Added GraphiteWriter tests.

Not much of a test, but at least it makes sure the writer is not completely broken ...
Reverted changes to example file
Merge pull request #182 from jmxtrans/introduce-guice-as-di-framework

Introduce Guice to the game.