commons-lang upgraded to 3.3.2, latest bugfix release
Remove workaround that is no longer necessary
Each sweep gets its own executor

This is so that when there are multiple sweeps, there is no resource
contention.
Remove a FIXME that is no longer true
Findbugs 2.5.4
Upgrade JavaNCSS and JDepend
Disable Findbugs and enable JDK8