gui: always get screen resolution from graphicscontext

This allows GFX to modify this info for stereo modes and calibration
overlay: don't take cropping offset into account for overlays

This breaks 3d modes and serve very little use in the real world
v(dpau/aapi): respect source rectangle on render

This fixes 3d rendering and should allow cropping to function. This should
also solve any issues with pixmap being larger than source video video
vaapi/dxva: disallow larger than 1080p video's for decode

This can crash drives on sandy bridge systems and likely others
too.
guilib: reset pixelratio of RES_WINDOW when requested

Fixes default button in calibration window.
guilib: add accessor for CPoints in CRect and constructor
renderers: rename stereo 3d mode flag to more distinct name
added: support SBS and TAB display of xbmc gui
dvdplayer: factor out render flags from player
dvdplayer: pass stereo_mode to renderers and select what to render
d3d: support anaglyph stereo rendering
gl: support anaglyph and interlaced stereo rendering
gl: support stereo rendering using opengl builtin system
[3D] add a global toggle to enable/disable stereoscopic related features and moved interaction with stereoscopic related settings to a central stereoscopics manager
[3D] observe changes to the stereoscopicmode setting and push changes to the GraphicContext instead of having the context constantly checking the setting
[3D] add cActions to cycle through stereo modes and toggle it on/off
[3D] move stereomode detection from filename to stereoscopicsmanager and make the flags configurable via advanced settings.
[3D] add stereoscopic mode "mono" (2D)
[3D] add stereo mode info to stream details and make it available to skins via the GUIInfoManager
[3D] add GUI stereoscopic mode to GUIInfoManager to have it available in skins