changes endpoint from reader/topics to read/tags
updates Blogs I Follow and Posts I Like to use read endpoint
adds isWPCom boolean to ReaderPost
stores is_external data in isWPCom. updates social buttons to use isWPCom
supports featured_media object on read endpoint
Merge branch 'develop' into issue/1018-reader-endpoint

Conflicts:
	WordPress/Classes/ReaderPostView.m
converts tabs to spaces and other general style cleanups to match the style guide
changes references from "topics" to "tags"
converts some tabs to spaces
updates odd ternary operators
Merge pull request #1276 from wordpress-mobile/issue/1018-reader-endpoint

#1018 changes reader endpoint from reader to read