[Rd] Bindings for updated widgets in Tk 8.5.x

[Prof Brian Ripley]

Tk 8.5.x is starting to trickle down to Linux distributions and the next 
release of R for Windows will ship with 8.5.1 (the binary builds of 
R-devel already do).

According to http://www.tkdocs.com the new themed widget set has much to 
recommend it, and it certainly looks much better on MacOS and Windows.

I've added bindings to package tcltk for R-devel, and taken a quick look 
at what would be needed to convert package Rcmdr to make use of them.  in 
many uses they are a drop-in replacement (e.g. ttkbutton for tkbutton), 
but some of the customizations (fg="red") have different names 
(foreground="red", which also works for tkbutton) and others are replaced 
by the theme.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595