`brew cask-tests` collected the test results in an improper way so that it reports a false success in certain situations.
Specially, the session under BrewTestBot always reports success regardless of the test status.
With this update, the exit code of `brew cask-tests` is 1 when the test fails, and then CI preperly works.

Otherwise there's an error which is a regression on previous
functionality. This mirrors `rm -f` which doesn't fail if a file doesn't
exist.

Also changes exceptions.rb to use Formatter.url

Trying to uninstall a non installed Cask made this test fail.
This commit remove that and thus this test passes.
Note that every Cask is uninstalled after each test case.

Prevents namespace conflict with vendored ruby-macho.

This allows us to filter out weak linkages during audits, preventing
a false error from occurring when the dylib cannot be found.

This brings fixes for behavior expected in #1460.

e.g. this changes:

```
To re-install google-chrome, run:
  brew cask uninstall --force google-chrome && brew cask install google-chrome
```

To:

```
To re-install google-chrome, run:
  brew cask reinstall google-chrome
```

It's not necessary to make this a hard failure so don't (and this makes
it more consistent with `brew.sh`).

Fixes #1462.

Prevents namespace conflict with vendored ruby-macho.

This allows us to filter out weak linkages during audits, preventing
a false error from occurring when the dylib cannot be found.

This has been deprecated for quite a while now so disabling seems
reasonable.

November 1st 2016 has come and gone so it's time to disable this.

Also, add comments explaining why the things that have been whitelisted
have been (to avoid more being added without good justification).

Given how common it is for formulae to hard-code `etc` and `var`, check
for those paths (`/usr/local/etc` and `/usr/local/var`) when determing
relocatability.

It's more useful to be able to "bless" an existing bottle to be used on
later OSs (e.g. where it cannot yet be built) than it is to have to
create a new, identical bottle just to have a different filename.

Look at HOMEBREW_PREFIX rather than HOMEBREW_REPOSITORY for the default
Caskroom location.

Also: freeze the relevant arrays.

Add static libs and dylibs commonly put in /usr/local/lib by Symantec Endpoint Protection to the brew doctor white lists

This avoids issues with names containing special characters like e.g. [

Fixes #1431

...and update man pages where applicable

This will ease user anxiety when `brew install foo' is typed but nothing
seems to happen.

This audit check ensures that certain build dependencies
are explicitly marked either as `:build` or `:run`.
It seems to have been lost in #927.
It was also adjusted in #1290.

Ensure that the name is suffixed with whitespace or quotes.