Cleanup SvpSalGraphics LineGeometry creation

Target is to less modify the given PolyPolygons to
allow better buffer/reuse. To do so, multiple steps
need to be taken to make the creation of cairo_path_t
correct and effective.

Adapted AddPolygonToPath to no longer add a fixed
PixelOffxet of (0.5, 0.5) for LineDrawing. Moved that
at all places to set the needed linear transformation.
Some places which know to work in DeviceCoordinates got
directly adapted. The creation of geometry for polygon
paints that use line and fill no longer offsets by that
values for fill now (which should be better)

Adapted AddPolygonPath to use the closed information from
the given Polygon geometry - this is used in Win Gdiplus
for years and shoud be safe

Adapted AddPolygonPath to do correct PixelSnap when
a ObjectToDevice transformation is used. This requires
to have the ObjectToDevice transformation in the method
and using it and it's inverse

Adapted AddPolygonPath to support PixelSnapHairline which
now needs to be supported in the VCL-layer. Adapted the
BufferedData stuff accordingly (and saw that the old
solution for this snap was not used - sigh)

Corrected ::drawLine to correctly do PixelSnap if needed,
version before would have lost it

Change-Id: I5e8f71f7439b21f58561da5770b9054236a33235
Reviewed-on: https://gerrit.libreoffice.org/60083
Tested-by: Jenkins
Reviewed-by: Armin Le Grand <Armin.Le.Grand@cib.de>