Renamed com.github.jreddit.message.Comment to MessageComment in order to avoid confusion with the com.gihbub.jreddit.comment.Comment. The first is a comment(like a reply) from a message, while the latter is an actual Comment
Moved CommentsSort to Comments package and added missing CommentSort options
Added InvalidURIException to deal with Invalid location requests. Added it to the GET method
Renamed TypePrefix to Kind (more accurate naming for the reddit "kind" of a post), and added 2 more Kinds: LISTING and MORE
Merge pull request #63 from RaulLepsa/master

Some refactoring and improvements