Mostly related to the newer ways we’re handling versions and the
incoming deprecation of devel-only, head-only and versions.

Disallow file separator in version strings.

bottles: --force-bottle feigns or_later.

When reproducing issues with software that hasn’t been bottled yet on
your version of macOS it can sometimes be helpful to use `or_later`
bottle functionality i.e. just use the bottle for the latest version of
macOS available. This maps well to the existing `--force-bottle`
argument so it will now act as if the latest bottle has a `or_later`
ending.

cask depends_on arch: remove everything but 64-bit intel

keg: update installed dependency resolution

Closes #1525. (See there for a motivation for this change.)

ENV/super: fix set_cpu_flags stub.

It should accept arguments.

Fixes https://github.com/Homebrew/homebrew-core/issues/8362

keg: handle dependencies of moved/renamed formulae

Remove `:bsexec` parameter from `SystemCommand`.

In #1497 I switched from Keg#to_formula for comparing kegs to formulae
to comparing the name and tap in the keg's tab to the name and tap of
the formula.

However, this fails to match if the name and tap of the formula have
changed since the keg was installed, so it's clearly better to use
Keg#to_formula where possible, and fall back to the information in the
tab when #to_formula can't be used.

formula, ARGV: don't output duplicate formulae.

keg: fall back for dependencies of buggy tabs

keg: don't return nil dependencies

keg: fix fallback dependencies with multiple kegs

If you specify a formula more than once or it exists in the Cellar with
an alias name and the main name (e.g. `qt` and `qt5`) you can see the
same formula showing up more than once. Instead, resolve these output
lists of formulae such that they are unique based on their `name`. This
doesn't use `full_name` as it's `name` that's use for the `Cellar`.

This is a proper fix to the problem addressed by #1510.

The problem arises when f_kegs is nil, which can happen if the name and
tap used to install a keg don't match the name and tap currently
associated with its formula (i.e. if it's been renamed or moved).

This reverts commit d7e72899.

See https://github.com/Homebrew/brew/pull/1752#discussion_r94257147

formula_versions: handle uncommitted formulae.

ENV: deprecate old methods.

audit: improve reliability of homepage audit.

See https://github.com/Homebrew/brew/pull/1750#discussion_r94243825 for
discussion.

Removes Tab#reliable_runtime_dependencies? in favour of returning nil
from Tab#runtime_dependencies if the list is unreliable.

Because Homebrew 1.1.6 hasn't been tagged yet, tabs created in tests
aren't created with a homebrew_version that marks the
runtime_dependencies in the Tab as reliable, so there are some tests
that fail. To work around this, I've had to add a line to some tests
that explicitly overrides the homebrew_version in the Tab. This is
really ugly though, so they should be removed as soon as possible after
1.1.6 is released.

These should have been deprecated long ago but we didn’t really have
the necessary framework to do so.

This will use Curl’s default user agent to reduce homepage errors and
provides a function that can be used for other audits to perform
similar tests on URLs.

uninstall: a couple of dependency error/warning message improvements

Otherwise an uncommitted formula can trigger an invalid `brew audit`
result.

Fixes #1731.

Fixes #1524.

This method isn't used any more