Checkpoint: replaced cfg_scripts/checkout-*.sh with checkout.sh.
Bug fix: checkout.sh now returns a success status.
Builds GD-Perl from source; misc. other cleanups; tested.
Synched with head.
Merged from master.
Added GD shrink test that uses the resample mode.
Now uses an original image (taken with a digital camera) instead of
a generated image.
Bug fix: import option parser.
Added Vagrant config. to enable multiple cores in VirtualBox.
Removed junk comments from Vagrantfile.
Added truecolor-enabled version of shrink.
Added name-mangling to output files to distinguish them by script.
Switching to Ruby for scripting GD

Unfortunately, the Perl GD interface doesn't let me control whether
or not the image is true color or indexed and it was easier to rewrite
the script than fix GD-Perl.
Installs the FFI gem now.
Removed Perl tests from the list in all_benchmarks.
Moved all Perl tests to subdir 'unused' to make their current status clear.