[xmonad] idea: split XConfig definition into its own file

Hi all, How do people feel about splitting the definition of XConfig out of Core.hsand into its own file, XConfig.hs? (It could then be re-exported from Core.hs, of course, so no changes would be required to anything else.) The point of this would be so people who are trying to write their xmonad.hs and want to see what fields are available don't have to wade through all of Core.hs to find it. Such an XConfig.hs would also be a good place to provide some nice, detailed Haddock documentation explaining what each of the different fields are, and how to use them. I'd be happy to make the changes myself, just thought I'd run it by the list first to see what people think. -Brent