patch to support SVG and PGF output for qwtplot3d-0.2.7

[Gerard V. <ger...@gr...>]

Hi Micha,

attached is a patch to support SVG and PGF output
for QwtPlot3D-0.2.7.

Warning, you have to apply the patch manually
because I worked on the qwtplot3d source tree
after cleaning it up to facilitate editing 
(replacing tabs with two spaces and removing or
 replacing the CR's with NL's).

Regards -- Gerard