[Development] Proposal: Change Qt Slogan

[d3fault]

I think we need a slogan change so as not to lie to our users.

Old Slogan: Code Once. Create More. Deploy Everywhere.
New Slogan: Code Once. Create More. Deploy Everywhere that supports OpenGL + v8.

The reasons are self-explanatory.
The v8 part might only be true for the 5.0.0 release... but it appears
the OpenGL requirement is here for good.