Add `Pokemon.prototype.updateDetails()`

Allows you to change values in the object without creating a whole new
one.

Also improved `Pokemon.prototype.update()`
Update `Data.Tiers`

Added names, short names, and Doubles
Add `Data.getSets()`
Move `loadDropdowns()` to `Display`

Also add handlers for '.set-select' elements
Show '.set-select', Add clearer messages for blank

fields
Add a LOT of things to `Display`

`Display.loadSets()`
`Display.makeSetDropdown()` Work with set selection

`Display.getSet()`, changes to `Display.getPokemon()`, most `Display`
functions can now accept 'p1' or 'p2' as arguments instead of a jQuery
object denoting the side.