Add tasklist and githubemoji extension for Python Markdown

Added github style tasklists and githubemoji extensions to Python Markdown

You can enable as seen below
```javascript
    "enabled_extensions":
    [
        "extra",
        "toc",
        "codehilite",
        "b64(base_path=${BASE_PATH})",
        "magiclink",
        "delete",
        "githubemoji", <-- Github emojis in Python Markdown
        "tasklist"        <-- Github style tasklists in Python Markdown
    ],
```