* système de modèle - extension de fichiers (backend - install - plugins)

* Fix #92 Utilisation du système de modèle
* Work #91 template - extension de fichiers
    * skin backend rename *.phtml to .tpl
    * app/frontend*: edit extension on display() call
    * plugin/contact/admin: edit extension on display() call
    * plugin/contact/skin.admin: rename *.phtml to .tpl
    * plugin/clearcache/admin: edit extension on display() call
    * plugin/clearcache/skin.admin: rename *.phtml to .tpl
    * plugin/translation/admin: edit extension on display() call
    * plugin/translation/skin.admin: rename *.phtml to .tpl
* Fix #88 Update Bootstrap 2.3.4 => 3 (backend)
    * Upgrade Bootstrap 2.3.4 => 3.0.0
    * Adaptation des fichiers du template admin
* Fix #90 Bug Liaison produits
* Fix #89 Bug ajout page cms enfant