Smartly display chat or edit button in profile.
Smartly switch drawer fragments on a delay or no delay depending on if the drawer is open.
Select nav items by enum name.
Move nav API from MainActivity to NavDrawerActivity interface.
Switch to chat from profile.
Merge pull request #140 from thehelpsf/jing-develop

Fix #69 Put a link from the Mentor profile page that takes the student right to chat.