[selectors, facet] make is_instance and other EClassSelector subclass gather entity classes from 'select' and 'filtered_variable' context information. Closes #1796732 This allow for instance to use the filter form on rqlst where the filtered variable is not selected

#! /bin/sh -e
#

if [ "$1" = configure ]; then
  if which install-docs >/dev/null 2>&1; then
    install-docs -i /usr/share/doc-base/cubicweb-doc
  fi
fi


#DEBHELPER#

exit 0