Added @Heydon's talk on effortless style

I think Heydon's talk is very inspirational and teaches us to look beyond classes to style our content. This in turn forces us to look at stuff like aria roles and states to style our content. I'd appreciate it if you'd watch the video and consider adding it to your list.
Merge pull request #2 from MichielBijl/patch-1

Added @Heydon's talk on effortless style