Add Multi-Markdown Table Support

Just wondering if table support (besides inline HTML tables) would be on the radar. I just added `'tables'` to the markdown object, and that seemed to be all that was necessary.

Line 107

Is:
```python
md = markdown.Markdown(['codehilite', 'fenced_code', 'meta'])
```

Suggested:
```python
md = markdown.Markdown(['codehilite', 'fenced_code', 'meta', 'tables'])
```