move entityNamespace setting and namespace utils to repo

- these are specific to the repo
- also moved related namespace utils to the repo

@todo: make things less static would be nice

Change-Id: I4acc406d7e1e893c8e67a2fe59d5566511011ac4
(minor) Snak.toJSON() now uses 'property' instead of 'propertyId' for snaktype

This has been wrong JSON generated before since the server side gave the type as 'property' field some time already and also the wb.Snak.newFromJSON() JavaScript function assumes 'property'.

Change-Id: If67815841bba30c2043a7d0fc32b746de7977b63
(minor) corrected json output of PropertyValueSnaks in JavaScript

The JSON returned by getJSON() is now the same as in the PHP SnakSerializer. Before this has been missing the datavalue type.

Change-Id: Iec051ef62e8fe44718abc2998344f6c7da170bd5
(hotfix) $prefs should be passed by reference

- $prefs should be passed by reference in the onGetPreferences hook;
not doing so, leads to the new preference not showing up for me (php 5.4);
according to the documentation of the hook, passing by reference is
the correct way;

Change-Id: Ia942f4cd9622b50f86a27e8d5dbc5dc53ae17a2c
Prevent interface event propagation

Prevent interfaces from triggering events that EditableValue is aware of already. (See inline documentation for more information.)

Change-Id: I426988ff6bfd923e5911a18d73130028f6f43d82
(bug 42954) Anonymous user edit warning on entity page

Whenever starting edit mode, a warning tells the user that the IP will be recorded when saving.

Change-Id: I341c826de65204978315f502748814843921a906
(bug 42954) Anonymous user edit warning on create item/property pages

When not logged in, a warning will be displayed on the "create item" and "create property" pages.

Change-Id: Id660dcf9cf774ac032218bf208d5431b23e39236
Merge changes Id660dcf9,I341c826d,I426988ff

* changes:
  (bug 42954) Anonymous user edit warning on create item/property pages
  (bug 42954) Anonymous user edit warning on entity page
  Prevent interface event propagation
Merge "(hotfix) $prefs should be passed by reference"
Merge "(minor) Snak.toJSON() now uses 'property' instead of 'propertyId' for snaktype"
Merge "(minor) corrected json output of PropertyValueSnaks in JavaScript"
Merge "move entityNamespace setting and namespace utils to repo"
Adjusting wikibase JS API to changes made in Snak.toJSON

Adjusting to changes made in Iec051ef6 and If6781584.

Change-Id: Ib6505186304c28ea5c454b163a07ebe1ce06e419