Allow users to choose add-on weight

[nate]

The add-on weight system is a good one that can fix compatibility problems rapidly. But add-on authors aren't the best people to be choosing the weights-- users are.

It's perfectly possible to have a ring of three add-ons, each that works when loaded on top of the next add-on, but breaks when loaded on top of the previous add-on. Those authors could not choose appropriate weights. Their users, however, could, because the users would know which two of the three they were using.

But add-on users are loathe to edit init files-- both because they're concerned about validation, and because they don't know what a .teaa is, much less how to assign weight.

So I propose a pair of simple ^v buttons on the add-on screen that allow users to shift the relative weights of loaded add-ons. ^ could increase the weight until it was just higher than the next highest add-on; v could decrease the weight until it was just lower than the next lowest add-on.

[Hachem_Muche]

This is a good idea and wouldn't be too hard to do.

It should also be possible to reorder the addon priorities (or remove an add-on entirely) for saved games from the character load screen, because not all add-on conflicts are obvious from the start or may develop from later add-on versions.

The user-specified add-on weights could be stored in a game config file, and the order for each individual character would simply be specified in the desc.lua file by the order of the add-on list.