Make Timer.Context closeable.

This way it can play nicely with Java 7's try-with-resources.
Renamed Sample to Reservoir.

Should have followed @joewilliams's lead on this a while ago with Folsom.
Remove the old, outdated Markdown docs.
It is the future now.
Make registry fields final in reporter builders.
Oh hello huge chunk of dead code!
Log debug error with buffer pool loading.