Update Ember.js to 1.6.1
Remove unused helpers
Change tabs to work with routes and outlets instead of helpers

When I started working on settings I had a bit different vision on tabs
and I've added that code prematurely. It seems that the best way to go
is to create separate routes and controllers for each tab - that way we
can just rely on Ember.js for customizing, not some custom code in tabs
helpers etc.
Send record to buildURL method when it's available

For some cases (like coming env vars) we will need to also pass a
repository id to the URL, so I'm passing it from createRecord and other
methods which handle records.
Use settings-form class for settings form
First stab at env vars
WIP on env var settings
fixed alignment on vertical elements
began styling of edit and delete actions
First stab at ssh key form
Display settings in repo pane
Add loading indicator for settings
Finished all action hover states
Merge branch 'ps-env-vars' of github.com:travis-ci/travis-web into ps-env-vars
Final touches on env vars
Ssh key form styling and polishing
Bring back proper pusher key for dev
Allow to disable ssh_key
Proper field name on ssh_key form
Highlight invalid textarea