requirements: enable userpaths by default during evaluation
Infer path to be added for requirements that search PATH

When a requirement is specified like:

  satisfy { which "foo" }

There is no reason that we should inject all of ENV.userpaths! into the
build environment. Instead, infer the directory to be added to PATH from
the Pathname that is returned.

This is another step towards condensing the "which program" requirements
down into a one-liner DSL element.
superenv: allow -W[alp], style arguments to pass through

We already (correctly) allow -Wl, style linker arguments to pass
through; extend this to -Wp, (preprocessor) and -Wa, (assembler).

Fixes #17252.
rbenv-bundler: add warning recommended by upstream(s).

Closes #17262.
References https://github.com/carsomyr/rbenv-bundler/issues/32
jenkins 1.499
casperjs 1.0.1

Closes #17268.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
poppler 0.22.0

Closes #17264.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
Git-TF 2.0.1

Closes #17263.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
uwsgi 1.4.4

Closes #17261.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
z 1.5

Closes #17259.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
vim 7.3.780

Closes #17269.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
tomcat 7.0.35

Closes #17272.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
CurlApacheMirrorDownloadStrategy: fetch mirrors in JSON format

Closes #16457.
rbenv-vars 1.2.0

Closes #17276.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
chromedriver 26.0.1383.0

Closes #17277.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
pygobject has gintrospection disabled, no need to pull package

Closes #17271.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
Add Homebrew-completions to search
brew search looks in samueljohn/python, too.

Closes #17267.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
Move rails-completion to https://github.com/Homebrew/homebrew-completions
Move knife completion to https://github.com/Homebrew/homebrew-completions