Update to use Streamhub SDK 2.6

- upgrade to be compatible with SDK 2.6 (include View module, use cajon)
- pass 'count' param to HotCollectionsClient
- include 'url' attribute in Collection created by HotCollectionToCollection

I am trying to bundle this application (with a custom view), other Livefyre applications, plus the SDK itself, into a local build.  But the dependency on an earlier incompatible revision of the SDK is messing me up.  I also added the 'url' attribute to the 'Collection' so it's usable in templates, and fixed a bug where 'count' was not being passed to the 'hottest' API request.  Please vet this.