closes #345410: two_lines_rset, two_cols_rset, two_etypes_rset are badly named replaced by multi_lines_rset, multi_columns_rset, multi_etypes_rset, all taking optional 'nb' argument allowing to specify and exact count. Bw compat is kept, usage of deprecated function updated in cw itself. Also drop custom at_least_two_columns selector (in views.plots) since it was the same as multi_columns_rset. Hopefuly the renaming will help in avoid such pb... We should now decide if we want to deprecate one_* selector in favor of multi_*(nb=1). See note on this at then end of selectors.py

/*
 *  functions specific to cubicweb on google appengine
 *
 *  :organization: Logilab
 *  :copyright: 2008 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
 *  :contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
 */

/* overrides rql_for_eid function from htmlhelpers.hs */
function rql_for_eid(eid) { return 'Any X WHERE X eid "' + eid + '"'; }