move all of the scraper-specific documentation out of README.md and link out to the wiki
move all of the scraper-specific documentation out of README.md and link out to the wiki

Nolawee/congress,unitedstates/congress,unitedstates/congress,chriscondon/billtext,boblannon/congress,Nolawee/congress,sunlightlabs/congress-opencongress,chriscondon/billtext,boblannon/congress,sunlightlabs/congress-opencongress