Added support for checking in users

- added page with user list
- added calls to api
- added support for checkin call in the api client
- adjusted frontend/css
Merge branch 'new-api-client-refactoring' into checkin-page

Conflicts:
	composer.json
	composer.lock
	src/Raffle/MeetupService.php
Refactoring for new API Client.
Updating to latest API client
Updating api client.
Added OAuth Handshake.

Checkin page now gets the user credentials to do checkins, no longer a security issue.
Working draft of checkin functionality
Merge pull request #13 from AmsterdamPHP/redis-checkin

Local Checkin