the base game entry is now called "Doom 3 (base game)" instead of
"dhewm3", which should be more obvious, and the d3xp entry now reads
"Resurrection Of Evil (d3xp)" instead of just "d3xp", which certainly
is clearer. d3xp now is also always second in the list (if installed)
Added the freshly supported perfected_roe and sikkmodd3xp mods to the
list of mods that need fs_game_base d3xp set, so they can be started
from the menu.
also added an entry for r_gammaInShader to Configuration.md
incl. setting in SettingsMenu
With SDL 2.0.5 and newer this change is applied immediately,
2.0.0 to 2.0.4 need a vid_restart
(with SDL1.2 we don't support it at all)
apparently this happens sometimes, but not often enough to reproduce
properly?
also some small changes (mostly formatting) to Configuration.md
refs #540
