Update Rubocop

This change updates the version of Rubocop used, and makes changes to
make Rubocop happy.

It also updates to the latest version of Tomcat.
Merge branch 'update-rubocop'
Safe Tomcat download location

Previously the download location for Tomcat (from a mirrored location)
was unsafe.  When new versions of Tomcat were released, they old links
expired and builds would break.  This change updates the location of
the downloads to be from a permanent location.

This change also updates the Travis configuration to work against the
latest Tomcat 7 and 8.
Merge branch 'nebhale-tomcat-download-location'
Move tasks to Rakelib

After some more research, it has become apparent that the appropriate
location for custom Rake tests is actually the rakelib directory, not
the rake directory.  This change moves those files, and updates the
require statements such that none of them require require_relative any
longer.
Merge branch 'nebhale-rakelib'
Update Rubocop fix

An earlier commit removed some code to satisfy Rubocop, but in the
process made some variables public that do not need to be. This change
fixes that.
Merge branch 'fix-rubocop'
Update Rubocop configuration

Previously the rubocop configuration didn't check the Rake file or any
of the custom Rake tasks.  As these are all code worth checking, this
change updates the Rubocop code to check them.  It also fixes the
problems that Rubocop found.
Merge branch 'nebhale-rubocop-configuration'