Feature/tabularlight

render csv files with pandas if available or python's csv module if not. Also render tsv files.
When you find yourself writing code like `for n in range(len(data))`, you're often better off using `enumerate` instead:
```python
for index, value in enumerate(dataframe[fields[0]]):
    ...
```
See https://www.jeffknupp.com/writing-idiomatic-python-ebook/. I think I have a copy of this somewhere if you want to borrow it.