Likebutton merged to dev

[TraceLarson]

Like button adds functionality to DetailsPage:

• Hides or shows like button if user is logged out/ logged in
• If user presses like button and is logged out they will be send to login page
• if user presses like button and is logged in:
  • Likes are increased and updated on page
  • If user has already liked the property, no action is taken
• Refactored some code, added some comments in backend routes, updated all componentWillMount lifecycle methods into componentDidMount.
• Changed history.push('/Login') to window.location.href=/Login in user actions