Feature request: add tableGrob() objects

[LineStaunstrup]

Hi Thomas,

Thank you for a nice package that is build up in a very intuitive way. A feature I am missing though is the possibility to add tables as well as plots. I know you can do this with grid.arrange(), and I really miss that feature.

/Line

[thomasp85]

Duplicate of #13

I'm planning to add a wrap_grob() function that would allow adding arbitrary grob objects