Use ENV['HOMEBREW_SOURCEFORGE_MIRROR'].

Closes Homebrew/homebrew#15642.
Closes Homebrew/homebrew#17368.

Better version of ed357d.

References Homebrew/homebrew#15711.
References Homebrew/homebrew#17361.
References Homebrew/homebrew#17437.

Also, move the line containing `info`, `home` and `options` to the top of the
list as users should be running these before installation.

Ref. Homebrew/homebrew#13224.

Fixes Homebrew/homebrew#17434.

c.f. Homebrew/homebrew#17361.

Fixes Homebrew/homebrew#17422.

Closes Homebrew/homebrew#13349.

Closes Homebrew/homebrew#17181.

Allows a formula to selectively disable bottle pouring.
e.g. the default Boost bottle does not work with a brewed Python.

Fixes Homebrew/homebrew#17142

Closes Homebrew/homebrew#14270

Closes Homebrew/homebrew#15711.

Gmock and GTest should not be installed system-wide.

Closes Homebrew/homebrew#17358.

Revert "Prevent linkapps from creating duplicate aliases"
Revert "linkapp: create Finder aliases"

This reverts commit e1a68f1ffbac9dc8209cc9ac2c8f2e34d11867af.
This reverts commit bf2e6023d1bac08739b4562e19e07db448f0aba3.

Closes Homebrew/homebrew#15308.

Fixes Homebrew/homebrew#17403.

Closes Homebrew/homebrew#17383. Closes Homebrew/homebrew#17384.

Fixes Homebrew/homebrew#17379.

We skip build-time deps when installing from bottles. However, the
current logic only considers the root, rather than the actual dependent
formula. Given

  A (bottled)
  |__B (not bottled)
     |__C (build-time)

C will be pruned from the effective dependency tree of A. This is wrong,
because C is required in order to build B.

Fix this by examining the current dependent rather than the root.

Fixes Homebrew/homebrew#17356.

Closes Homebrew/homebrew#17338.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>