Remove ISimpleLayoutCapable from news folder.

News folder is not really a simplelayout container.
Having the ISimpleLayoutCapable on the folder results in reindexing all containing
news items on every change on a news item (!) because the news items implement
the simplelayout block interface (because of the image).
This is a huge performance impact.
Merge pull request #116 from 4teamwork/jone-newsfolder-remove-sl-capable

Remove ISimpleLayoutCapable from news folder.