Added speechIntent constants

I added the speechIntents object containing several constants that
extensions can register to handle.  This allows extensions access to our
complex grammars in a very simple way.  If more than two extensions are
registered for the same speechIntent, then the user is given a choice as
to which to use.  That preference is then saved until another app
subscribes to that speechIntent.
Merge pull request #2 from miller9904/master

Merge pull request #1 from Skylight-Software/master
Merge pull request #2 from Skylight-Software/master

Sync merge