Preserve property keys as cell class names

[planemad]

This is such a beautiful library, thank you. Noticed that the class names for the td cells substitue underscores in the property name to hyphens.

In my data, the property name is mla_name but in the html I can see the td class set to mla-name-td

It would be a lot more convenient if the property name mla_name was preserved as the class names for consistency.