added a top-level README file

git-svn-id: svn://svn.code.sf.net/p/uhexen2/code/trunk@5336 eaf649e6-6c13-0410-b194-84221022858e
added a top-level README file

git-svn-id: svn://svn.code.sf.net/p/uhexen2/code/trunk@5337 eaf649e6-6c13-0410-b194-84221022858e