Feature request: jobify sdf generation.

[paulhoux]

Would be nice if creation of the SDF for a single glyph is done on a separate thread, then copied to the texture using a quick blit. If you'd use jobs (task based system), you could optionally wait for all glyphs to be rendered and all cores could help, speeding things up considerably. Jobs aren't easy to program, though, but I have a nice C++14 implementation lying around that could be a great addition to Cinder in the future. One can dream. Simple threads will work, too, of course.