[EditQueue] WIP: Contents are now versionable

* Modified install.sql for both contents and pages
* Added object type to objectType.xml
* Added AbstractUltimateVersionableDatabaseObject.class.php
* Modified Content, ContentAction and ContentEditor
[EditQueue] WIP: Finished system implementation

* Added page_version table to install.sql
* Added missing foreign keys to install.sql
* Added missing versionable object type for pages in objectType.xml
* Added VersionHandler and VersionCacheBuilder that utilize the needed paradigma
* Modified Page, PageAction and PageEditor to make them version ready
* Modified Content, ContentAction and ContentEditor to use the new VersionHandler
[EditQueue] WIP: Major revamp

* Uses now custom version system
* Fixed many issues arising out of that
* Pages are no longer versionable
[EditQueue] WIP: Introduced unique versionID

* the previous versionID became versionNumber
* versionID is now primary key
[LanguageSystem] WIP: Updated create* and update*

* The create* and update* methods in ContentAction have been updated
* They use the new language system now
[EditQueue] ContentVersion uses new lang system
[EditQueue] Added groupOptions

* Modified userGroupOption.xml
* Added missing language variables
[EditQueue] Fixed cache reset

* Added methods createVersion and deleteVersion to resetCache list
[EditQueue] Uses version now version cache

* Added cache classes
* Modified Content to reflect the changes
Merge branch 'feature/301' into dev