Window size change detection

[volca02]

SDL has SDL_WindowEvent in SDL_Event in case the window changed size/position...

We should notify render service about the fact the window changed size, render service would then notify ogre.

[volca02]

if (event->type == SDL_WINDOWEVENT) {
    if (event->window.event == SDL_WINDOWEVENT_RESIZED) {
        .... event->window.data1 x data2
    }
}