VTests: allow test to pass if SSIM > 0.999
VTests: allow test to pass if SSIM > 0.999

this accounts for single pixel differences
paroj/ogre,OGRECave/ogre,paroj/ogre,OGRECave/ogre,OGRECave/ogre,paroj/ogre,OGRECave/ogre,paroj/ogre,paroj/ogre,OGRECave/ogre