Update pygments files to latest version

[JonoYang]

prog_lexers.py and pygment_lexers.py has diverged from the latest version of Pygments and should be updated.

[JonoYang]

prog_lexers.py and pygments_lexer.py has been updated to the latest version (v 2.7.1). The unit tests have also been enhanced with a data-driven test.