[PATCH] SVG import: keep aspect ratio when transforming viewbox to viewport

[Chr. Rossmanith]

Hi,

bug 47451 has a test doc (svg) attached which isn't imported correctly 
by LibreOffice. One problem is that the aspect ratio is changed because 
the viewbox is zoomed to be of identical size as the viewport. I've 
changed the zoom to be the same for width and height.

Christina