Mavenizing, use lore instead of name, cleanup

I intended to just fix an interaction problem with my plugin (pickup event wasn't checking for a cancelled event), but I ended up doing a lot more than that. Feel free to ignore this pull request, if you want.

- Mavenized plugin for easy building. It should still be simple to build without Maven if you prefer.
- Money item drops will now use a friendly display name, and the amount is in the lore. Just in case it ends up in your inventory somehow
- Will not process a cancelled ItemPickup event