Use an ordered dictionary as a base type for LFSContentCollection
Use UIGraphicsBeginImageContextWithOptions for Retina images

Also prefix static constants used in cell and detail views.
Fix a lazy access issue in LFSContent

Also unify object insertion/addition code in LFSContentCollection
Temporarily cache cell height in content object

This way we avoid creating and configuring a cell twice. However,
this is not ideal as it breaks MVC. In future commits, consider using
KVC to associate content objects with cell heights without content
objects’ knowledge.
No need to initialize LFSBasicHTMLLabel more than once

(When used for calculating row height). Also correctly
sort content stream by eventId.
Remove knowledge of cell height from the model object

This “fixes” MVC. Model object no longer needs to “know”
what the cell height is.
Merge branch 'master' of github.com:Livefyre/StreamHub-iOS-Example-App into dev
Merge pull request #39 from Livefyre/dev

Use an ordered dictionary as a base type for LFSContentCollection