Mod4

## Feature spec
- user_sign_in_spec
- user_interacts_with_queue_spec

## Unit and functional tests
- Macros
   - set_current_user
   - current_user
   - clear_current_user
   - sign_in
- Shared examples
   - require signin
- <strong>Refactored existing tests to use above</strong>

## Gems
- Capybara
- Launchy

## Views
- remove duplicate id's from QueueItems#index form