[texworks] Early thoughts

[Karl Berry]

    Yeah, you'll never be able to get 100% of the cases but I *believe*  
    (at least) you'll be able to get a fair majority.

Heuristically guessing the engine from regexps worries me a bit, because
I fear that users will be quite confused when the guess is wrong.

Can we have or is there also a supported way to unambiguously specify the
engine, e.g., a first line of
%&latex
or, for context,
% engine=luatex language=uk

Thanks,
k