cpplint README does not specify Python version

[achekery]

Please specify Python version for reference. Python versions 2.X and 3.X have some syntax differences. However, the intended version is not specified in cpplint README.

$ cpplint.py --help
/cygdrive/c/work/scripts/cpplint.py:5864: Warning: 'with' will become a reserved
 keyword in Python 2.6
  File "/cygdrive/c/work/scripts/cpplint.py", line 5864
    with open(cfg_file) as file_handle:
            ^
SyntaxError: invalid syntax

$ python --version
Python 2.5.2