add Configuration.get_boolean()

--HG--
extra : rebase_source : 7a957aafb9c02b9248e15d1c32e44d78556eeee6
add new configuration setting devel.auto_reload that will automatically
reload the application when the classes, templates or modules directory changes.

--HG--
extra : rebase_source : 96981ff57d69b053cd87bd3ff1db444c5646f1ed