Promote apps in catalog to Templates

When adding CAMP specs to the catalog check if they describe an entity implementing Application and if so use a TEMPLATE instead of ENTITY item.
Good point, would've been better to remove the new line. This is already merged with https://github.com/apache/incubator-brooklyn/pull/220 though.

I have extracted the remaining test fixes in https://github.com/apache/incubator-brooklyn/pull/235 (not related to the changes).