Create directories when a path is specified in the --output option

[brushmate]

Fixes #512

[coveralls]

Coverage remained the same at 81.649% when pulling c56fc4a on yieldlab:create-directories into bf57c4d on Rebilly:master.

[brushmate]

The Travis build failed because a record key for cypress is missing:

Opening Cypress...
You passed the --record flag but did not provide us your Record Key.
You can pass us your Record Key like this:
  cypress run --record --key <record_key>
You can also set the key as an environment variable with the name CYPRESS_RECORD_KEY.
https://on.cypress.io/how-do-i-record-runs
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! redoc@2.0.0-alpha.21 e2e-ci: `cypress run --record`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the redoc@2.0.0-alpha.21 e2e-ci script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm ERR! A complete log of this run can be found in:
npm ERR!     /home/travis/.npm/_logs/2018-05-29T09_17_18_292Z-debug.log
The command "npm test && npm run e2e-ci" exited with 1.

[RomanHotsiy]

LGTM 👍
Thanks! I will release a new version of CLI later today