emf+: emulate hatch with color blend

Conflicts:
	cppcanvas/source/mtfrenderer/emfplus.cxx

Change-Id: I2ac8f790c79c269d4c1fa650e703c3645c567ca4
Reviewed-on: https://gerrit.libreoffice.org/10436
Reviewed-by: Andras Timar <andras.timar@collabora.com>
Tested-by: Andras Timar <andras.timar@collabora.com>