Async and Await support

Added async and await support.
Enhanced debugging with causality traces and no longer step into library code.
Added ContinueWith method to be able to catch a cancelation and continue the promise chain.
Reduced memory when Promise.Config.ObjectPooling is set to Internal or All.

Capture Values

After much work put into this project, this is the first versioned release.
It's not a v1.0 release yet because there is still more work to be done, but it's at a good, useable point now.