Rename logo@2X.png -> logo@2x.png and fix errors building css
Switch OAuth backend, fixes T285

Summary:
- install `league/oauth2-server` with composer
- uninstall `bshaffer/oauth2-server-php` from composer
- remove `modules/koauth`

Test Plan:
```
bin/behat -c application/tests/behat.yml application/tests/features/api.oauth.feature
```

Maniphest Tasks: T285

Differential Revision: https://phabricator.ushahidi.com/D120
add migration for new oauth server, under oauth-leage group
implement league storage interfaces for client, scope, and session
fix migrating down oauth-league
remove oauth2-0-1 migrations
fix some bugs in storage
add DI for oauth servers
implement action_post_token using new server
implement api access checking with new server
implement action_get_authorize using new server
implement (badly) action_post_authorize
this does not work, but i want to save it for later
add jquery.cookie plugin
add default scopes and client via migration
switch App.oauth to use client credentials for all access
di repo
remove user provider from oauth.js
fix bug in client storage
change js client login handling