(bug 43291) introduction of jQuery.wikibase.statementview

inherits from claimview, displayed in claimlistview on item entity pages. For now same
functionality as claims but different object. Introduced new template for this view.

- patchset 2: adjustments to selneium test
- patchset 5: adjusted JS wb.Statement.newFromJSON to new serialized statements structure.

Change-Id: Id74cde0758eb9d1759244e6ab2a89c8d1bb90959