comment/todo re: directory creation
show staging directory (caskroom) in doctor

refs #6471
User-friendly error messages for invalid options/arguments; fixes #5997

- Show a more user-friendly error message when dealing with an option whose (mandatory) argument is missing.

- Likewise, we show a more user-friendly error message when a given option is ambiguous. Examples:
    - Given `-f`, the parser successfully expands to `--fontdir`.

    - Given `-c`, we fail to expand because the parser can’t tell if the user means `--caskroom` or rather `--colorpickerdir`. This exception now results in a nicer error message.

- Some commands now result in a consistent error message when a required cask name is missing.
This affects all stable commands which require one or more cask names as arguments, i. e. `cat`, `create`, `edit`, `fetch`, `info`, `install`, `uninstall`, and `zap`.

- Up to now, the commands `cat`, `create`, `edit`, and `info` used to treat any unknown option as a cask name. This commit changes that behaviour to make it consistent to the rest of the commands (like `fetch`, `install`, `uninstall`, and `zap`), who have silently discarded any unknown option in the past, and continue to do so.
Add tests for #5997
Rewrite tests to make them work with Ruby 1.8
Bring the repo test back in sync with `.gitignore`.

This keeps the tests from failing, e. g. when developers use `rbenv` to run the 1.8-based tests.
Merge pull request #6493 from claui/fix-repo-layout-test

Bring the repo layout test back in sync with `.gitignore`
Upgrade Shortcat to 0.7.4
Merge pull request #6503 from crainiarc/shortcat

Upgrade Shortcat to 0.7.4
Merge pull request #6478 from rolandwalker/doctor_caskroom

print caskroom location in `brew cask doctor`
Add Rowmote Helper.app v3.9.4

Closes #6500.
Merge pull request #6504 from vitorgalvao/fix-6500

Add Rowmote Helper.app v3.9.4
Merge pull request #6491 from claui/issue-5997

User-friendly error messages for invalid options/arguments; fixes #5997
bump 1password to 4.4.2