Signonotron2 integration

@gtrogers
@pbadenski
@alexmuller
Verify user logged in with 'protected' decorator

@gtrogers
@pbadenski
Sign out page with bootstrap

@gtrogers
@pbadenski
Very quick styles for main and log out pages
'not authorized' page

@gtrogers
@alexmuller
@pbadenski
Logo to link to the homepage

@gtrogers
@alexmuller
@pbadenski
Navbar handles login/logout

@gtrogers
@alexmuller
@pbadenski
Tests for signon integration

@gtrogers
@alexmuller
@pbadenski
Flash message after user is signed in

@gtrogers
@pbadenski
Test for user having incorrect permissions

@gtrogers
@pbadenski
Merge branch 'master' into signonotron2-integration
Refactor to use flash messages consistently

@gtrogers
@pbadenski
Add bootstrap "row" class where required

@gtrogers
@pbadenski
Scope URL's with '_user'

Anything under '/' can be a bucket name, so we need
to scope with an underscore.
Also renamed login to sign_in to keep naming consistent.

@gtrogers
@pbadenski
Unit testing signonotron auth service

@gtrogers
@pbadenski
Update readme
README
Feature flag for sign on integration

@gtrogers
@pbadenski
Only using basic bootstrap css, removing extras.
Temp redirect /_user to index