buildProduction: Merge --jpegtran, --optipng, --pngcrush, --pngquant, --optimizepngs, and --optimizejpegs into a single --optimizeimages switch that does the right thing.

Part of #78.
Removed optimizePngs (doesn't work anymore).
Added optimizeImages binary.

It reads the image files specified on the command line, runs them through processImages, then writes them back to disc.

Fixes #80.