Update links in README to point to RDocs on RubyForge
Update links in README to point to RDocs on RubyForge

sjchakrav/mechanize,bugmelody/mechanize,sparklemotion/mechanize,uksa/mechanize,jeremiahmarks/mechanize,eligoenergy/mechanize,eligoenergy/mechanize,uksa/mechanize,bugmelody/mechanize,sjchakrav/mechanize,gchan/mechanize,gchan/mechanize,pwnall/mechanize,pwnall/mechanize,sparklemotion/mechanize,jeremiahmarks/mechanize,flavorjones/mechanize