[trunk] SVG export overlaps multipage scores

Steps to reproduce bug
1. Open "inv1" demo (or any multipage score)
2. File > Export... (and save as SVG)
3. Open SVG file in Inkscape

Expected behavior: Each page should appear side by side (same as it appears in MuseScore)

Actual behavior: Notation from every page of the score appear as overlapping elements on every single page of the SVG (see attached)

MuseScore version: r. 4994 nightly

(Operating System: Windows 7)