quick frontend, primitivus, wix: MUC private messages management

/!\ not fully finished, backend part is not done yet /!\
    - as resources are discarded to manage chat windows lists, a pretty dirty hack is done to work around this:
      full jid is escaped using a prefix (it becomes invalid and resource is preserved).
    - new quick_utils module, with helper methods. escapePrivate and unescapePrivate implementations
    - MUC private messages are not managed in Wix yet

frontends/src/quick_frontend/constants.py

@@ -0,0 +1,23 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+
+"""
+Primitivus: a SAT frontend
+Copyright (C) 2009, 2010, 2011, 2012  Jérôme Poisson (goffi@goffi.org)
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"""
+import __builtin__
+
+__builtin__.__dict__['const_PRIVATE_PREFIX'] = "@PRIVATE@"