Not quite a mass replacement as I've used OS X and Mac OS X where
describing specific older versions and added compatibility methods
for things in the DSL.

update-report: create top-level directories later.

Otherwise if they are created and empty they may be removed again
before we try to create the `/usr/local/bin/brew` symlink.

update-report: migrate /usr/local repository.

update.sh: turn origin/branch into a variable.

Migrate a HOMEBREW_REPOSITORY and HOMEBREW_PREFIX of `/usr/local` so
that the HOMEBREW_REPOSITORY is now in `/usr/local/Homebrew`. This gives
us more flexibility on changing the repository layout in future and
avoids putting junk in `/usr/local` when not necessary (e.g. our
`README.md`).

Rather than repeating origin multiple times.

Rubocop: apply auto-corrections and don't use hash-rockets

utils: convert formula name from pathname to string

formula: set TERM to dumb during test

`name` is passed as argument to Formulary.factory which could later be
downcased at formulary.rb:349, but Pathname doesn't have a downcase
method. Converting `name` to String as it should be fixes the problem.

Fixes #1000.

How-To-PR: both stable & devel in simple commit message

Improve legacy symlink migration.

Read the old symlinks and migrate them across rather than assuming a
unlink/link will work fine (as users have conflicts.)

ENV.no_weak_imports should be a no-op when Xcode doesn't support the
feature to avoid breaking builds with <= Xcode 7.

But remove some manual `.freeze`s on constants that shouldn't be
constants.

Move LinkedKegs migration.

Move the `LinkedKegs` migration into `utils.rb` so it can also be called
from `brew.rb` on startup.

os/mac: officially support Sierra.

Always run LinkedKegs migration (if needed).

test-bot: generate coverage reports on Sierra.

Ensure that `brew update` always runs the LinkedKegs migration if needed
as it may not have been run by `brew update` if it was using `--preinstall` or
a `git pull` etc.

Also, if the old paths still exist: just use them instead.

Finally, always try to unlink/unpin before link/pin.

Fixes https://github.com/Homebrew/homebrew-core/issues/4918.

We have a GM, a bunch of bottles and CI setup.

We may have two Sierra nodes available which could speed up this
relatively slow operation.

Move LinkedKegs/PinnedKegs/Locks from Library.

.codecov.yml: disable GitHub comments.

Software that tries to print different things (e.g. ANSI color) based on
different termcaps often relies on the TERM environment variable, and
could fail without it. This results in confusing test issues where
certain tests can be successfully run by users testing locally with TERM
set, but choke up on our CI.

Always setting TERM to dumb leads to better consistency between local
tests and CI tests, and saves much probing in certain cases.

These are annoying and the status check is sufficient.

update documentation to show the correct preferred simple commit
message format for combined stable and devel version updates

update-test: handle missing master branch.

Ensure it's always created.

Also, re-order `update-test` in `test-bot` (and `readall`) so they are
run before the test suites.

These don't make sense to be tied to the `HOMEBREW_REPOSITORY` but
instead should live in the `HOMEBREW_PREFIX` as they all relate to its
state.

Send coverage from Jenkins, don't run OS X Travis.