PATCH: merge calc geometry calls into convenience function

[Nate Lawson]

On Fri, 16 May 2003, Scott Long wrote:
> cam_calc_std_geometry() might be a better name.  I like the idea in any
> case.  However, could you hold off until after the 5.1 branch?

Of course.  This was just something I had in my tree that I wanted to get
out for review.  It is not being considered for 5.1.  I'd also like
comments about the location of the function and prototype (in cam.c and
cam_ccb.h).  This is a minor thing but good since several bugs were
uncovered in the previous cut/pasted functions.

-Nate