Merge pull request #149 from fredericbonjour/Admin

Updated Backoffice.
Refactor System Db Schema
Add Workflow Engine
Merge pull request #150 from inthause/workflow

Add Workflow basic implementation
US localization
change:initialize-plugin and change:initialize-model commands
Merge pull request #151 from franckstauffer/dev2

US localization (partial)
[REFACTOR] extend renamed to extends
[REFACTOR] Injection becomes replacer (in model and autoload)
Merge pull request #152 from franckstauffer/dev2

Refactoring of "extend" and "inject" on model. Class Injection renamed to Class Replacer
[FIX] normalization of model name
Merge pull request #153 from franckstauffer/dev

[FIX] normalization of model name
Refactoring Plugins setup
Fix tests
Merge pull request #154 from inthause/workflow

Refactoring Plugins setup
Added "DocumentList" directive to ease the creation of lists of documents.
Added Change main menu that slides from the left when clicking on the Change logo in the header. This menu can also be shown with Ctrl+Alt+M (not configurable for the moment).
Moved main menu controller into a separate file (menu.js).
Added "Back to home" link in main menu.
Use new "<document-list/>" directive.