Parameters
    ----------
    plugin_package : str
        Name of plugin package hosted on MicroDrop plugin index.
    plugins_directory : str
        Path to MicroDrop user plugins directory.

def uninstall(plugin_package, plugins_directory):
    '''
    Parameters
    ----------
    plugin_package : str
        Name of plugin package hosted on MicroDrop plugin index.
    plugins_directory : str
        Path to MicroDrop user plugins directory.
    '''
    # Check existing version (if any).
    plugin_path = plugins_directory.joinpath(plugin_package)

    if not plugin_path.isdir():
        raise IOError('Plugin `%s` is not installed in `%s`' %
                      (plugin_package, plugins_directory))
    else:
        try:
            plugin_metadata = yaml.load(plugin_path.joinpath('properties.yml').bytes())
            existing_version = plugin_metadata['version']
        except:
            existing_version = None

    if existing_version is not None:
        # Uninstall existing package.
        print 'Uninstalling `{}=={}`.'.format(plugin_package, existing_version)
    else:
        print 'Uninstalling `{}`.'.format(plugin_package)

    # Uninstall latest release
    # ======================
    plugin_path.rmtree()
    print '  \--> done'