Log Message:
Update to 9.0.0

Upstream changes:
9.0.0 (2016-11-02)

    BACKWARD INCOMPATIBLE Remove the attempted autodetection of requirement \ 
names from URLs, URLs must include a name via #egg=.
    DEPRECATION pip install --egg have been deprecated and will be removed in \ 
the future. This "feature" has a long list of drawbacks where it \ 
breaks almost all of pip's other features in subtle and hard to diagnose ways.
    Add a pip check command to check installed packages dependencies (PR #3750).
    Added option to allow user to abort pip operation if file/directory exists
    Added Appveyor CI
    Uninstall existing packages when performing an editable installation of the \ 
same packages (#1548).
    Pip show is less verbose by default. --verbose prints multiline fields. (PR \ 
#3858).
    Added optional column formatting to pip list (#3651).
    Add --not-required option to pip list to list packages that are not \ 
dependencies of other packages.
    Fix the build on systems with symlinked /tmp directory for custom builds \ 
such as numpy (PR #3701).
    Fix regression in pip freeze: when there is more than one git remote, \ 
priority is given to the remote named origin (PR #3708, #3616).
    Fix crash when calling pip freeze with invalid requirement installed (PR \ 
#3704, #3681).
    Support multiple --requirement files in pip freeze (PR #3703).
    Implementation of pep-503 data-requires-python. When this field is present \ 
for a release link, pip will ignore the download when installing to a Python \ 
version that doesn't satisfy the requirement.
    Pip wheel now works on editable packages too (it was only working on \ 
editable dependencies before); this allows running pip wheel on the result of \ 
pip freeze in presence of editable requirements (PR #3695, #3291).
    Load credentials from .netrc files (PR #3715, #3569).
    Add --platform, --python-version, --implementation and --abi parameters to \ 
pip download. These allow utilities and advanced users to gather distributions \ 
for interpreters other than the one pip is being run on. (PR #3760)
    Skip scanning virtual environments even when venv/bin/python is a dangling \ 
symlink.
    Added pip completion support for fish shell.
    Fix problems on Windows on Python 2 when username or hostname contains \ 
non-ASCII characters (#3463, PR #3970, PR #4000).
    Use git fetch --tags to fetch tags in addition to everything else that is \ 
normally fetched; this is necessary in case a git requirement url points to a \ 
tag or commit that is not on a branch (PR #3791)
    Normalize package names before using in pip show (#3976)
    Raise when Requires-Python do not match the running version and add \ 
--ignore-requires-python option as escape hatch (PR #3846).
    Report the correct installed version when performing an upgrade in some \ 
corner cases (#2382)
    Add -i shorthand for --index flag in pip search
    Do not optionally load C dependencies in requests (#1840, #2930, #3024)
    Strip authentication from SVN url prior to passing it into svn (PR #3697, #3209).
    Also install in platlib with --target option (PR #3694, #3682).
    Restore the ability to use inline comments in requirements files passed to \ 
pip freeze (#3680).
    Deprecate --default-vcs option (#4052).