ReaderPosts: Fixes FetchPosts Threading
ReaderPosts: Updates LikePost Call
ReaderPosts: Updates FetchPostsForTopic Call
ReaderPost: Adds assertion
ReaderPosts: Updates ToggleFollow Call
RaderPost: Fixes LikePost Call
ReaderTopicDidChange note should always be posted on the main queue
ReaderPosts: Updates CoreData Usage + Addressing code reviews
Merge pull request #2600 from wordpress-mobile/issue/2596-fixes-coredata-threading-glitch

Issue/2596 fixes coredata threading glitch