Add support for src_rect and dst_rect in engine.xml:
	<rect name="src_rect" l="0" r="1920" t="0" b="1080" />
	<rect name="dst_rect" l="0" r="1920" t="0" b="1080" />
src_rect determines the area in the world bounds to display. dst_rect determines the window size and scale as it appears on the final monitor. These functions obsolete:
	<rect name="local_rect" l="0" r="1920" t="0" b="1080" />
	<float name="window_scale" value="1.0"/>
	<point name="window_pos" x="10.0" y="100.0" z="0.0" />
and also the I think currently hidden:
	<text name="scale_world_to_file" value="true" />