Fixes bug when working with multiple WCF.EditableItemList objects

Currently, `WCF.EditableItemList._data` is shared between multiple objects which has the unexpected effect that you find objects of the second list in the first list.
Added support for application based option types
Fixes error message
Optimized UserGroupOptionPackageInstallationPlugin

Closes #1010
Merge pull request #1008 from Gravatronics/bug/multipleEditableItemList

Fixes bug when working with multiple WCF.EditableItemList objects
Merge pull request #1006 from Gravatronics/enhancement/afterDeletionCodeOptimization

Optimizes AbstractCategoryType::afterDeletion()
Merge pull request #1005 from Gravatronics/bug/categoryDeleteJS

Fixes WCF.ACP.Category.Delete
Merge pull request #1009 from Gravatronics/bug/errorMessage

Fixes error message
Removed wcfNestedSortable(), use nestedSortable() instead

Fixes #1007
Merge branch 'master' of github.com:WoltLab/WCF
Fixed routes not properly handling ACP requests
Fixes bug (missing __menuItem) in pageMenuItemList.tpl

Also does some formatting for better readability.
Adds missing language item
Adds interfaceName to proxy actions
Added TYPE_BOOL
Merge pull request #1011 from Gravatronics/bug/pageMenuItemList

Fixes bug (missing __menuItem) in pageMenuItemList.tpl
Merge pull request #19 from Gravatronics/bug/languageItem

Adds missing language item
Merge pull request #1012 from Gravatronics/enhancement/JSProxyActionInterfaceName

Adds interfaceName to proxy actions
Adds missing implementation of IToggleAction
Removes IPositionAction

Use ISearchAction instead!