1) Fixed the trailing space issue in text decoration attribute value.

2) Changed the SVG export suite in order to make it more reusable for
other tests.

3) Added a unit test for testing that text decorations are exported
correctly.

Reviewed-on: https://gerrit.libreoffice.org/19870Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Andras Timar <andras.timar@collabora.com>
(cherry picked from commit 50506421)

Conflicts:
	sd/qa/unit/SVGExportTests.cxx

Change-Id: I2bd71974242a0007726fbdd5ef5637a9ec62fd47