This adds a command line argument `--indent_after_first` which sets the
indentation of all lines after the first one, e.g. SELECT, UPDATE, etc. For
example:

    $ sqlparse/__main__.py -r sample.sql
    UPDATE foo
      SET a = 1
      WHERE a > 2
        AND a < 10;

    $ sqlparse/__main__.py -r --indent_after_first sample.sql
    UPDATE foo
    SET a = 1
    WHERE a > 2
      AND a < 10;