Add primitive caching.
Fix a few typos.
Add a config option to disable caching.

By default, caching is disabled in developer mode, so that changes
happen immediately. Caching can also be disabled by setting the relevant
config flag in config.xml.
Add a config option to disable minification.

Source is not minified when in developer mode, but can also be disabled
when not in developer mode, with the minificationDisabled flag in
config.xml.