[R] ridge() function and coxph

[Terry Therneau]

I need to add a belated acknowledgement to my prior comments.  Thomas
Lumley has also been a significant contributer to the survival code.
Until I moved my development from Splus to R he was the primary
maintainer of the R code, he tightened up a lot of the C code to make
sure it would work on multiple architectures, and added several
functions.  Merging our two code bases back together was a significant
effort when I switched.

Terry Therneau