First version of variable Workload prices

Selection done through menu bar. Still a bit to clean up as far as what
information to show in selector. Leaning towards Workload size.

Grouped Item GUI updates into GUIManager (out of from within a random
panel [craftcomponentpanel] of all things).

Current refreshItems() in DataManager is(will) probably causing a lot of
overlap due to Item's updateCost() branching out, as in a Craftable is
probably getting hit for every time a Craftable component calls
updateCost().