various fixes.

builders: run repo updates only if repo is updated.
setup.sh: fix path of apt pkgdb
pinstall.sh: generate png icons from svg
ubuntu basesfs: add rsvg-bins for converting svgs
re-arrange rox data, while keeping compatibility with previous setups.

.config/rox.sourceforge.net/ROX-Filer is now a symlink to Choices/ROX-Filer.
builders update

- Support for %cutdown dev, which exports dev files to devx-holder
- Support for %import, which imports arbitrary dir for inclusion to chroot.
  This feature is mainly for importing dev files when building devx.sfs.
- Updated support for %cutdown nls which exports to nls-holder
  (for maing nls.sfs)
- Support for specifying pkglist from command line.
- Updated basesfs/devx pkglist for slackware (examples of all above) and
  ubuntu too. Cutdown doc gtkdoc nls is now default for both ubuntu and
  slackware.
builders: clean up devx-holder and nls-folder when %cutdown command is used.
builders: more cutdown for nls: take care of /usr/lib/locales too
/etc/profile.d: only executable files are considered.
symlink rxvt to xterm if it does not exist.