If there's dead symlinks in there they should be removed.

formula_installer: remove dependency_installer.

This is no longer needed as the reason it was added (argument
sanitisation) is now done properly.

Also, remove `skip_deps_check?` in favour of `ignore_deps?` as it too is
no longer needed.

Fix dependency option handling.

reinstall/upgrade/install: always output options.

- formula_installer: only recompute dependencies when necessary i.e.
when a bottle pour fails.
- formula_installer: re-add accidentally remove dependency options
- dependency: missing options are only those that actually exist on a
formula

formulary: remap deprecated options from keg.

This is both easier for debugging and to communicate with users what is
being done.

When reading a building a formula from a keg (rather than e.g. from
name) then the deprecation options were not remapped correctly as they
are only done in `Tab.for_formula` and not `Tab.for_keg`. Ensure that
after we’ve created the formula that the `used_options` are remapped
correctly.

cask reinstall: download and verify cask before uninstall

Point to GitHub Releases in CHANGELOG.md

A lot of people (e.g. me in #1633) will look here and not find
anything. We should point them to the proper location.

Add a method for installing fish function files

os/mac: Remove mention of Mavericks bottles

bump-formula-pr: use correct version in download path when --version is specified

boneyard-formula-pr: make it more consistent with bump-formula-pr

tab: include HOMEBREW_VERSION

After Issue #985 was merged, bottles for Mavericks are no longer
being built, meaning installations are triggering builds.

Update the FAQ to show that builds will most likely now be
triggers on Mavericks since their bottles are not being generated.

When a --version is specified, use this specified version in the name of
the downloaded file rather than the default that is parsed from the URL.
For instance,

  brew bump-formula-pr --devel \
    --url=http://www.zsh.org/pub/development/zsh-5.2-test-2.tar.gz \
    --version=5.2-test-2 zsh

should download to $HOMEBREW_CACHE/zsh-5.2-test-2.tar.gz (correct
behavior after this commit) rather than
$HOMEBREW_CACHE/zsh-2.tar.gz (wrong behavior before this commit).

Make its behavior more consistent with that of bump-formula-pr.

Make its behavior more consistent with that of bump-formula-pr.

Use `launchctl` to get running processes by bundle ID.

xcode: cleanup Xcode::Version usage.

Don't wrap `MacOS.version` which does comparisons properly already and
avoid stupidly long lines.

Refactor Cask installer.

Fail if cask source already exists.

Fish shell allows third-party software vendors to put their own function files in a directory for their software.
For brew installed Fish shell, this is /usr/local/share/fish/vendor_functions.d

travis: use Xcode 8.1 on Sierra.

added "CLT" abbreviation after "Command Line Tools" in Installation.md doc

For code coverage from `brew test-bot`.

Closes: caskroom/homebrew-cask#27075