Added option for setting whether the front or back buffer should be read using --front and --back command line options.
Added option for setting whether the front or back buffer should be read using
--front and --back command line options.


XiaoCC/osg,omega-hub/osg,omega-hub/osg,ghub/osg,ghub/osg,ntoand/osg,XiaoCC/osg,stmh/osg,XiaoCC/osg,ntoand/osg,artoolkit/osg,stmh/osg,omega-hub/osg,koshman86/osg,stmh/osg,ghub/osg,ntoand/osg,omega-hub/osg,ntoand/osg,artoolkit/osg,stmh/osg,ghub/osg,XiaoCC/osg,stmh/osg,artoolkit/osg,koshman86/osg,koshman86/osg,koshman86/osg,XiaoCC/osg,artoolkit/osg