Big README update
Big README update

Cleaned things up a bit, made some parts more compact and tried to
expand the information in others. Also made some corrections (eg.
about the discoverResources method) and added an FAQ section as
well as an index.

simplecrawler/simplecrawler,cgiffard/node-simplecrawler,simplecrawler/simplecrawler,civalin/node-simplecrawler