various changes to the glviewport
including use of Qt5.2 openGL classes
fix warning/compile error with mingw
fix for missed gl updates under linux
added rgb16/rgba16 support without having to convert to rgbf first
added toggle for the interpolate pixels option
missing rename from intializationSucceded to initialized
cleaned up some old displayslot code and added displaying the image
zoomed out if it is larger than the viewport
change saving the window geometry to saveGeometry instead of manual
method and move it to closeEvent instead of main
removed unused code
added fullscreen and changed 1 to 9 shortcuts to select the active image
fix for crash caused by uninitialized opengl functions
added premultiplied color option to glviewport to avoid ugly color
fringes with transparent images with the default interpolation