VERSION file: master VERSION file is in base folder, symlinked from nx*/VERSION and hw/nxagent/VERSION.

  This commit removes the debian/VERSION file at makes it now unnecessary to
  copy/symlink the VERSION file at build time. These build scripts got adapted:

    debian/roll-tarballs.sh
    debian/rules
    nx-libs.spec

  Furthermore, all NX component now use the main VERSION file as reference.

    typechange: nxcomp/VERSION
    typechange: nxcompext/VERSION
    typechange: nxcompshad/VERSION
    typechange: nxproxy/VERSION

Add 400_nxcomp-version.full+lite.patch. Allow 4-digit version comparison during NX session handshake. (Fixes: #610).

* Split up patch 210 (for correct creation nx-libs, nx-libs-lite tarballs):
  + 210_nxagent_save_session_state.full.patch
  + 210_nxcomp_save_session_state.full+lite.patch

Add VERSION.x2goagent to package x2goagent package so x2goversion command lists up x2goagent in the list of X2Go server-side packages.