Fix #725 and #729.

Signed-off-by: David <db@d1b.org>
Clean up the _get_build_prefix code - close the open fd and print the error message if the fd could not be opened (denied).

Signed-off-by: David <db@d1b.org>
Update the code _get_build_prefix to raise an exception instead of sys.exit()'ing and also document that on windows user temp directories are already isolated.

Signed-off-by: David <db@d1b.org>
In the os.open call to get the fd to check if the user specific build directory
is in fact owned by another user - add the os.O_NOFOLLOW flag to not follow symbolic links.

Signed-off-by: David <db@d1b.org>
Provide a test to cover the changes to pip/locations.py regarding the use of
the_get_build_prefix method to create a user specific build_prefix directory.

Signed-off-by: David <db@d1b.org>
Also un-patch the patched getpass.getuser method.
Signed-off-by: David <db@d1b.org>
setup.py read function fix
update changelog and authors
update docs with new build dir
windows and other misc test updates
changelog fix
Merge pull request #780 from qwcode/pip_build_directory

/tmp/pip-build fixes