Feature request by user: add support for Rnw files

[daattali]

I've never used an Rnw file but once I look into it , it might not be too bad. Original poster

[daattali]

Anyone who is familiar with knitting Rnw files might find this fairly easy. I'll happily accept pull requests if anyone wants to help with this. Look at the code in core.R, it's well documented so shouldn't be too hard to add support for Rnw if you know how to do it