Improve existing why-perl6/examples: Make feed location-independent, update introspection and laziness to match slides, minor cleanups
Add channels, metamodel, simple-oo, and sort to why-perl6/examples/
Add a simple README for why-perl6/examples/
Minor fixes to why-perl6 talk
Add comments at top of example slides in why-perl6 talk that point to matching examples/ script
why-perl6 slides for Promises and Channels