Add ability to set exact resolution

[ks202005]

I'm using windowed mode, and I prefer 1280x960 as it's a nice size for games on a 1920x1080 monitor. However, I'm not able to set this exact size in the video options of the Cumulative Patch launcher (1024x768 is close, but a bit small, while 1280x1024 is too big and isn't 4:3, so the HUD is stretched slightly, at least for now).

The resolution option allows you to type a custom value, but doing this has no effect.

[recore67]

you can set a custom resolution to your liking by manually changing the ResX and ResY values in th2_opt.cfg accordingly.

Till now, all that the launcher does is make it simpler to adjust that cfg file with pre-set values before starting the game, I usually prefer doing it manually so i don't hassle with it everytime.