Don't warn about missing @Override annotations, for now.

A _lot_ of existing code is missing @Override annotations.
Fix method-should-be-static warnings from Eclipse.
Fix resource-leakage warnings from Eclipse.
Use System.err for printing out warning and debug messages.
Fix all the Javadoc warnings flagged by Eclipse.
Use diamond operator where appropriate. Thanks Eclipse!
Merge branch 'master' into language-specific-histograms