[cmake-developers] Add command line options for deprecation message control

[Brad King]

On 10/21/2015 06:01 PM, Michael Scott wrote:
>> should defer this part until after the main warning control
>> command-line options are worked out.
> That sounds sensible, I'll make the proposed changes to the cmake and 
> cmMessageCommand classes first, get some adequate tests in and then move 
> on to updating the callers.

Oops; actually by "this part" I was referring to the entire warning->error
upgrade feature.  Let's work out the command line options for the existing
deprecation warning/error options first and then extend capabilities as
a second step.  It will be easier to review in smaller pieces anyway.

Thanks,
-Brad