Feature request: key bindings to add an address to the to field, cc field, etc.

I guess a variant of insertText: could be implemented allowing something like:

( "insertHeader:", "to", "first@example.com, second@example.com" );

I'll consider that. I'm not quite sure it's the right way to solve this kind of request...

(If implemented like this then a clearHeader: variant would likely also be useful.)