Merge pull request #1 from phuongnq/master

change StoryBoard ID of MyList
Add Message and Notification to Storyboard

Just added skeleton view controllers and their class.
Wire transition to MessageList & NotificationList

Make transition from SidebarView to MessageListView and
NotificationListView
Temporarily added some AWSS3 function.
Need to consider whether user S3 or only Parse table is enough!
Fix some storyboard titles
Add PostAnswerViewController & some small refactorings

Mostly based on ShareViewController, but tried to add asAReplyTo
attribute.
Attaching asAReplyTo to answerVideo

Make sure every answerVideo be an answer to a specific questionVideo
Add postedUser to QuestionListView

query postedUser by video, then return the user’s displayname
modify myList - just show videos of type answer