Remove dependency inkscape: It's needed by svg-to-pixmap.mk, but not
for building jw-pkg. If anything, -devel should depend on it, but
that seems a little heavy handed and can be achieved by packages
which know that they include svg-to-pixmap.mk.
Add dependency cpio: Needed by pkg.sh to copy a the source file tree.
Will be removed again as soon as pkg.sh goes Python.
Signed-off-by: Jan Lindemann <jan@janware.com>