Pages for API token

Add pages to manage (CRUD) API tokens (access/secret keys). The entry is located on user settings page.

![selection_207](https://cloud.githubusercontent.com/assets/5958/4055003/e45688b2-2d99-11e4-9436-a259fccbbf40.png)

![selection_208](https://cloud.githubusercontent.com/assets/5958/4055004/e5ca2258-2d99-11e4-9944-fa191d053e80.png)