[cmake-developers] Setting includes, defines and other usage requirements with one command

[Stephen Kelly]

Brad King wrote:

>> I've implemented it in the tll-includes-defines branch in my clone. I've
>> only tested it manually though.
> 
> Yes, that looks good.  Please add tests covering each case:

I've pushed it again to my clone. 

Once the fix-target-property-commands topic is in master, we can rebase it 
if needed and get it merged to next.

Thanks,

Steve.