Coveralls update á la OSRA

PT Chore: https://www.pivotaltracker.com/story/show/80520490

- include Coveralls directives in Cucumber's env.rb
- create rake task to push _combined_ RSpec & Cucumber data from CI server to Coveralls
- update Travis config to use new rake task

#### Let's hope this works as well for us as it did for OSRA

Ping: https://github.com/NikitaAvvakumov