Bug fix #35179

Added provision for saved corrupt blend files - caused by a startup.blend 
addressing > 16 GB space, which was read in 32 bits.

Now an invalid screen will get removed immediate after read. Might give
a memory-not-in-memlist print, but that's quite safe.



git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@56509 954f8c5b-7b00-dc11-b283-0030488c597c