[bennu-portal] Complete Rewrite: Allowing more flexibility and integration

  * MenuItems are now split in MenuContainers and MenuFunctionalities
  * Added the concept of PortalBackend, allowing the various presentation technologies
    to integrate seamessly with bennu-portal
  * Added server-side layout injection for Backends that so require
[bennu-portal] Portal.js now uses Twig.js

  * Updated default theme accordingly
  * Twig.js is automatically loaded
  * Also improved handling of client-side modules in Twig.js
[bennu-admin] Completely rewritten the bennu-admin application

  * It is now built using Angular.js instead of Bankai
  * Updated to work with the new version of bennu-portal
  * Greatly improved the System Info panel, showing more JVM information and allowing Thread Dumps
  * Added a simple DomainBrowser UI, that allows navigating through the instance graph of the application
Merge pull request #109 from jcarvalho/feature/portal2

Portal 2
[default-theme] Minor Visual Improvements to the default theme

  * Added missing resources
  * Cleaned up some visual clutter
  * Small visual tweaks
[bennu-core] New Feature: New applications now have a visual wizard to configure them

  * The steps of this wizard are configurable, and any module can specify new steps
Merge pull request #110 from jcarvalho/feature/bootstrap

New Feature: Application Bootstrap
Removed deprecatd AuthenticationListener in favor of the synchronous version
Remove cross application server session invalidation
Removed accessibleGroups() feature
Reviewed group mechanics, separated persistent part from the group logic. Reviewed group language, now using antlr4 and solved all parenthesis issues. Improved error handling.
Add checksum to GenericFile
Create the concept of default file storage to handle unconfigured files
Extended file API to include an isAccessible(User user) method. New file type: GroupBasedFile that implements isAccessible with a Group
Migration instructions
migration
ArgumentParsers needs annotation
Fixed hashcodes on constantgroups
Checksum is readonly