wmde/WikibaseDataModel — pull request #329 by thiemowmde (2014-12-18 17:56:51+00:00)
Title: Optional Item constructor parameters

This is a part of #290. I hope we can at least agree on that. The two parameters made optional by this patch are:
* `$statements` are already optional in `Property`, but not in `Item`, which is just a bit inconsistent.
* `$siteLinks` are specific for `Item`s.