Help Messages

An updated PR from @beepted, @akittels, and @cj343 - thanks again, guys!

@reidka is still working on some text for the help messages.

@arkon, the css and general look could really use an upgrade, but I'm just letting you know for later. There's other stuff you're working on now that's more important (Prototype -> jQuery, mainly).

Since this is wrapping up a project from the winter, my inclination is to merge now and polish later. Review away!
Maybe capitalize "csv" and "zip?"