Changes to a directory, yields, and changes back.
    Additionally any error will also change the directory back.

    Usage:
    >>> with safe_cd('some/repo'):
    ...     call('git status')

def safe_cd(path):
    """
    Changes to a directory, yields, and changes back.
    Additionally any error will also change the directory back.

    Usage:
    >>> with safe_cd('some/repo'):
    ...     call('git status')
    """
    starting_directory = os.getcwd()
    try:
        os.chdir(path)
        yield
    finally:
        os.chdir(starting_directory)