Expand the glReadPixel width to a multiple of 4, if it isn't already, to work around miscalculation of pixel store. ATI graphics miscalculated glReadPixels when buffer width not 4 byte aligned  https://tracker.physiomeproject.org/show_bug.cgi?id=2697 Merged from cmgui_2_7_0_plus_fixes revision 8042
Expand the glReadPixel width to a multiple of 4, if it isn't already, to work around miscalculation of pixel store.
ATI graphics miscalculated glReadPixels when buffer width not 4 byte aligned 
https://tracker.physiomeproject.org/show_bug.cgi?id=2697
Merged from cmgui_2_7_0_plus_fixes revision 8042


cmiss/cmgui,cmiss/cmgui