[WIP] Update the credits from IndieGOGO

[NQNStudios]

Starting to implement #377 / NQNStudios#1

First of all, I've made a file, DONORS.md, which contains the names IndieGoGo gave me for every backer who selected the "Name in Credits" reward.

I'm going to email every backer and make sure they get a chance to verify their name, change it, and if they didn't select the reward, maybe it was an accident, so I'd add those names later.

My plan is for this file to be the only place the names are staged in the repository, so we're not maintaining the same information mirrored in other places. This file can be copied into the data folder, and the ingame credits can parse it by pulling lines that start with bullet points.

[CelticMinstrel]

Definitely need to verify exactly what name they prefer to be referred to by. Maybe there are some who'd like to use a pseudonym instead of (or in addition to) their real name.

With that many names, it seems iffy to put them in the scrolling credits (though I wouldn't say it's impossible). Regardless of whether they go in the scrolling credits, they should also go in the about dialog… which probably means the about dialog will need to be cleaned up to avoid the "two overlapping text blocks that properly line up based on mutually exclusive whitespace" mechanic.)

I don't really like the idea of parsing this file to pull out the bullet points, but I guess there are worse ways to do it? There is also the possibility of parsing it at build time though, and dumping the output into the strings folder.