Primary Keybindings, elemental use hints, and overly deep pockets

Just a few small fixes in:

• Primary Keybindings were not saving properly; this should be fixed.
• There are now hints about how to switch elements when you find a new element and how to use more powerful spells when you upgrade your elemental gems.
• You should no longer be able to pick up more than you should in certain circumstances.

Cheers!