Revision 2479

	Refactored svgexport tests: 9 double tests runs eliminated;
	code size reduced by 8 lines.

	* Extensions/svgexport/test/test_svgmapwriter.py:
	(class TestWithDC): Renamed to BaseTestWithDC, moved to top.
	(class BaseWithDCtools): New, subclass from BaseTestWithDC.
	(class TestDrawSplines): now subclass from BaseTestWithDCtools,
	this fixed the double running of the nine tests of TestVirtualDC.
	(class TestVirtualDC): Using self.dc and self.file from setUp().