Address improper use of recipients field - fixes spree-contrib/spree_email_to_friend#56
Remove unused parameter hide_recipients

hide_recipients parameter is not used. We simplify gem
functionality by removing it. Related tests are also removed.
Remove html from flash message

Fixes spree-contrib/spree_email_to_friend#55
Merge pull request #57 from chaboo/incorrect_recipients

Address improper use of recipients field.
Test 2.1.5
Use bin folder for Rails 4.x
Update README.md etc.

- Move contributing information to own document.
- Fixes badges.
Update dev dependencies.

- Use document style for spec runs.
- Include pry in spec for easy debug.
- Keep RSpec 2.14 to avoid spec refactor for now to avoid merge
conflict with pending pull request.
- Gemfile don’t need to declare master branch because it default.
Fixes deprecated Spree::Config[:site_url]

It use fallback for older Spree versions.