Added additional safeguards to the code that loads savegames, to make sure that worlds are loaded correctly. Now only one thread may load the world at a time, even if a new LoadingActivity is created, for example by rotating the device.
git-svn-id: https://andors-trail.googlecode.com/svn/trunk@250 08aca716-68be-ccc6-4d58-36f5abd142ac