fix false positive tests due to assert tuple syntax
Merge pull request #2088 from qwcode/false_positive

fix false positive tests due to assert tuple syntax
Add --user options to pip list and pip freeze
Added functional tests
Added unit tests for get_installed_distributions user_only
Fixed finctional test for pip freeze
Merge pull request #2093 from pfmoore/freeze_user

Add --user options to pip list and pip freeze
Clarification of pip install -U help
Merge pull request #2098 from pfmoore/docfix

Clarification of pip install -U help
Fix to tox.ini so that pip.exe doesn't try to overwrite itself on Windows
Python 2.6 doesn't support python -m for packages
Merge pull request #2099 from pfmoore/toxfix

Fix to tox.ini so that pip.exe doesn't try to overwrite itself on Window...
unpack_url: session only needed for unpack_http_url
vcs: add documentation to VersionControl class
cleanup: use "with open()" to open files
freeze: simplify code and use with open()