Support python 3.6

[xuqingfeng]

It is available for Python 2.6, 2.7, 3.3, 3.4, 3.5

Currently for 3.x newest version is 3.6.0.

[Xuanwo]

Welcome for your pr.

[tankywoo]

@xuqingfeng Thanks for your report, I will test 3.6.x when it is unmasked in my local environment.

[guyskk]

在Python3.6下运行有个DeprecationWarning：

python3.6/site-packages/pygments/util.py:26: DeprecationWarning: Flags not at the start of the expression '<(.+?)(\\s.*?)?>.*?</' (truncated)
  tag_re = re.compile(r'<(.+?)(\s.*?)?>.*?</.+?>(?uism)')

需要升级 Pygments: https://bitbucket.org/birkenfeld/pygments-main/pull-requests/687/pull-flags-out-of-regular-expressions/diff

[tankywoo]

@guyskk 感谢提醒