Set `HOMEBREW_NO_EMOJI` and `HOMEBREW_CASK_OPTS` in `cask-tests`.

Cask update error msgs

audit: don't complain about trailing whitespace.

This is handled by `brew style` now.

hbc/cli/style: bump RUBOCOP_CASK_VERSION

tweak 'brew deps' zsh completions

Formatter: identifier: only reset color, not full styling

Don't choke on invalid UTF-8 in `file` output

scm/git: more old OS X versions tweaks.

- unset IFS to fix version parsing on older Bashes
- reuse existing HOMEBREW_MACOS_VERSION if it’s available
- set rather than unset popup_stub

shims/scm/git: fix on old OS X versions.

dependency_collector: need xz dep on <= macOS 10.8

On older versions of OS X (i.e. pre-Mavericks) `xcode-select` is not
required to be set when using the CLT. Fix this behaviour so `brew
update` doesn't tell everyone on that configuration to `brew install
git`.

Update FAQ.md

Mountain Lion: http://opensource.apple.com/source/libarchive/libarchive-25.1/config.h
  `/* #undef HAVE_LIBLZMA */`

Mavericks: http://opensource.apple.com/source/libarchive/libarchive-29/config.h
  `#define HAVE_LIBLZMA 1`

### Is there a glossary of terms around?
All your terminology needs can be [found here](docs/Formula-Cookbook.md#homebrew-terminology). results in 404 error

Sometimes `file` output contains data from the file under examination,
which may include binary data that does not represent valid UTF-8
codepoints. String#split dies if it doesn't understand the encoding, so
tell Ruby to treat `file` output as a bytestring.

Fix wrong ordering on when clauses in audit.rb

Refactor `puts_columns` to allow `$stderr.puts_columns`.