Tabbed content on user profile & Scrum link fix

PT Chore: https://www.pivotaltracker.com/story/show/78203768
Also, added changes that cover PT bug: https://www.pivotaltracker.com/story/show/78650308

* Added tabs to profile page and a custom text if user has not added any bio test
* Removed sponsors bar from user profile
* Updated `custom.css` and `layouts_navbar` with code previously submitted by @marianmosley & @decareano 
Do we have a test that asserts that this link present? Having assertions of non-existence without asserting the existence in the first place can be dangerous, it is easy for the test to pass even when things change.