[Rd] ASCIIfy() - a proposal for package:tools

[Arni Magnusson]

Thanks Duncan, for considering ASCIIfy. I understand your reasoning.

This is a recurring pattern - I propose functions for core R, and Greg 
catches them from freefall :)

I'm delighted with ASCIIfy being hosted in gtools. The R and Rd should be 
ready as is.

Cheers,

Arni