Add settings profile, admin and ssh key pages

[bantic]

The ajax is not yet wired up for editing name, password,
email or adding ssh keys.

refs #51 #66

The pages are now working for displaying data. The link to settings is obscured by the navbar (#67) but you can go directly to /settings to see the pages.

Notes for wiring up the data are in a separate issue.

This PR makes the pages look like:

@sandersonet for you cc @mixonic

[bantic]

Still to do:

• DRY ssh tests
• allow user to delete ssh key
• better styling for ssh adding, form, errors
• test that create SSH key posts to /users/:user_id/ssh_keys (Due to a bug with the interaction between unit test isolated containers and Ember Data, this is much harder than expected. The URL interactions are implicitly exercised by the acceptance tests, and that will have to be enough for now, but I will revisit this later)

[bantic]

Still to do:

• change password
• change email
• change name

[bantic]

This is ready to go now.
The user can add/delete SSH keys and change name, email and password.
@mixonic ready for your review.
This depends on changes to auth that are in https://github.com/aptible/auth.aptible.com/pull/109.

Some screencasts:

• change name:
  
• change email:
  
• add/delete SSH key
  

[bantic]

The dependent PR in auth has been merged, so this PR is no longer blocked on anything.

[mixonic]

Sweet. I will take this and maybe push it up into application or auth adapter if I can get the logic right.

[bantic]

I was thinking that maybe buildURLWithPrefix could take a map of verbs -> prefixes, so it would be, like: buildURLWithPrefix({'POST': {'users': 'user.id'}});. Not sure how difficult that would be but it probably makes some sense, since the paths are definitely verb-dependent. I am pretty sure the GET for ssh_keys is also non-prefixed (like the DELETE).

[bantic]

@mixonic all set now

[mixonic]

I've rebased this and force pushed it to your branch @bantic. Will merge when the tests go green