UI message generalisation
remove uniconv dependency, as is done in cdr_input: on windows we dont use uniconv script
Uniconvertor import extension changes for Win32 - Fixes LP# 197617
All extensions are now propper XML files with a namespace and all validate against the new inkscape.extension.rng RelaxNG schema.
added extensions for importing various Corel DRAW file formats and CGM files -- all using UniConvertor