Add row options

[ghost]

Hey, I needed some id tags and classes for each table row for handling rows, styling, etc., so I added two simple options to the settings. First option is 'rowId' which displays the document _id for each row. Second option is 'rowClass' which lets you add custom row classes. I updated the README.md as well.

[aslagle]

I can see how this would be convenient, but it isn't a good way to use the html id attribute - it would be better to use a custom attribute like row-id.

Also I'm not sure why you need it, since you can get this._id from the event handler. Is there a case that doesn't work for?

The rowClass option is reasonable, but it might be better if it accepted a function, so the class could be based on the contents of the row? it could work with either a string or a function.

[brugnara]

Does this patch allow to add custom class based on rob object values?

I'm guessing something like angular-way:

{ red: obj.qnt == 0 }

If yes, this would be awesome.