* Remove deprecated features at React v15.5

- [x] React.PropTypes
- [x] react-addons-pure-render-mixin
- [x] react-addons-test-utils

* Uncommented out & Add browserify_rails options

* re-add react-addons-shallow

* Fix syntax error from resolve conflicts

* follow up 59a77923b3

Add the same UI that already exists for blocked users for muted
ones and add it to the "Getting Started" menu.

Try to fix Travis CI setup

the public timeline has been using

Currently we have the problem where the follow request button is missing
from the Follow request tab. This means that when you visit that tab you
either have to press the back button in the browser or re-enter the home
page, which breaks the app flow.

This will resolve that issue by adding a new back button to that tab,
in the same way that the public timeline, and favourites have.