Document supported browsers

[shvaikalesh]

I believe the same runtimes we support in Chai: Node 0.10 (soon 0.12), IE 9+, latest Safari/Chrome/Firefox, Firefox ESR.

EDIT: if we agree on this, regular expression used to extract function name from it's source code could be a bit simplified.

[keithamus]

Proposal for simplification @shvaikalesh?

[shvaikalesh]

Node 0.10+ is good with names, so are the latest Safari/Chrome/Firefox, Firefox ESR. RegExp is only for IE9+. Thus we can drop handling comments (tried IE10, latest Safari/Chrome/Firefox, they all omit comments), methods (we don't), generators in regexp to make it faster & more readable.