Onscreen IDE & dynamic instant update [_v0.5.4_]

UPDATE :
[X] bugfix : I forgot to clear Ctrl down status when go back to IDE
[X] bugfix : I forgot to hide buffer viewer before shooting the scene
[X] the log over scene texture is saved per OS, since the letters arrangement is different on each OS.
[X] a buffer which doesn’t have a camera will be destroyed too, i.e. when an error occurs after buffer creation but before setting the camera for it.
[X] upon IDE/scene switch, the cursor hidden status is preserved.
[X] programmatic pointer movement is disabled when you go back to IDE. It will be repositioned to the last recorded resting coordinate at your next jump to scene, so you won’t get sudden movement if you use e.g. FPS camera controls. I do FPS all the time myself.
[X] the status bar is simple skinned and exploited a bit further to display some infos : errors count (per file), and the usual messages displayed at screen center are also displayed here too.
[X] better appearance consistency of tabs and status bar at different window resolutions.