Add support for python3 and compiled pyc file format

[ZiqianXu]

1. Specify the MIME type and extension for which to add support text/x-python: .py application/x-bytecode.python: .pyc
2. Share an example file python3 source file with shebang /usr/bin/python3 or /usr/bin/env python3

python compiled file .pyc

Thanks for looking into this!