Adding array comparison methods

Allows comparison of two arrays (just values, just keys or keys and values) while ignoring the item order. You can use callbacks, too.
Code styling
Code styling 2

The other changes are kind of acceptable, this actually makes the code harder to read and less structurized.
Bug fixing

... and is a possible source of mistakes
Adding wcf\system\Callback type hint
Type hint null
Merge pull request #1155 from PhrozenByte/enhancement/ArrayCompare

Adding array comparison methods
Removed obsolete icon path
Adds page title for category list page and add/edit form
Preventing first page menu item being disabled

Fixes #1156
Allow different dataType value for WCF.Action.Proxy
Added template event for Open Graph Protocol
getRequestURI() is now static
Added namespaces for open graph protocol
Removed obsolete code
Merge branch 'master' of github.com:WoltLab/WCF