Bug fix when effect doesn't support tile, clear the rect to renders before appending the RoD !
Cleaner autosaves when creating nodes
Quit global thread pool when exiting an AppInstance + fixed text renderer.
Initializes timeline markers on the curve widget correctly + also refresh image when auto contrast in enabled
Merge branch 'workshop' of https://github.com/MrKepzie/Natron into workshop

Conflicts:
	Gui/Gui.cpp