Fix parsing `--require-sha` and `HOMEBREW_CASK_OPTS`.

High Sierra: more initial support

tty: handle non-tty stdin.

When stdin is not a tty then the message `stty: stdin isn't a terminal`
will be produced. Silence this message and fall back to `tput` when it
fails and default to 80 if we get no results at all.

Follow-up from #2714.

undefined local variable or method `ruby_version' on macOS 10.13 beta

cmd/reinstall: Fix reinstallation of formulae without bottles

Remove duplicates repo from Acceptable formula doc

xcode: expect 8.3.3/recognise 9.0 on 10.13

Duplicates repo is deprecated

Reinstallation of non-bottled formulae was failing because it
used a deprecated method.

Signed-off-by: Bob W. Hogg <rwhogg@linux.com>

mac/version: add High Sierra symbol

pull_spec: use stable, non-fork PR for patch expectation

Fix internal links on the manpage

Fix `rubocop` in `brew audit`.

Refactor `FormulaVersions`.

Fix boolean types