Clean up the behat suite

* Split Application and Filesystem contexts
* Convert most steps to Turnip
* Combine redundant steps
* Replace stream magic with stubs
* Use Symfony\ApplicationTester instead of our own
Type/doc fixes
Simplify how interactivity is set
Replacing progress formatter
Whitespace
Use travis's containers
Removing unused tag
Merge branch 'master' into refactor/behat-context-cleanup
Only have one beforeScenario per context
Format Describe step more similarly to Run step
Move sudo stanza
Merge pull request #593 from ciaranmcnulty/refactor/speedup-travis

Use travis's containers
Fix visibility
Missing field
Use custom matchers for readability
Moving custom matchers to separate classes
Merge pull request #591 from ciaranmcnulty/refactor/behat-context-cleanup

Clean up the Behat suite