Update installation instructions

[joseasoler]

[QUOTE=Jet;13843682]Installed 0.5.0-beta2 over a patch o installation, renamed mod dir from "Fall from Heaven 2" to "Fall from Heaven 2 ExtraModMod", and got "GFC Error: fails to initialize the primary control theme" crash on startup until I followed the instructions in [url]http://forums.civfanatics.com/showthread.php?p=6564074#post6564074[/url], which fixed it.[/QUOTE]