[ODE] more c++, auto-enabling

[Matthew D. Hancher]

Okay, I added support for StepFast1, auto-disabling, and auto-enabling
to the C++ wrapper.  This made me notice something I had forgotten
about: auto-enabling looks to be only supported by StepFast1.  I don't
see any compelling reason for this; shall I port it over to plain step
and submit a patch?

The auto-enabling functions would then be renamed without the SF1
suffix, with deprecated #defines supporting the old names, I suppose.
I didn't include the SF1 suffix in the names of the C++ wrapper
methods for now, since it felt wrong, but that would be easy to change
if anyone disagrees.

( Patch in the same place: http://www.media.mit.edu/~mdh/odecpp/ )

Matt

Matt Hancher
NASA Ames Research Center
Official: mdh at email.arc.nasa.gov
Personal: mdh at media.mit.edu