Upgraded sequence editor UI

[SteveMyres]

I'd like to request a refresh on the sequence editor configuration UI.    Get all the glitches out of saving our display preferences in Windows 7 and later (or just make all the colors, background, default foreground, and syntax, select more freely and the selections stick), OR

Change sequence editing to use a commonly available external editor like Notepad++, if this would be compatible with keeping the ability for runtime changes to the DF application.

Thanks!