Revise README to reflect version 3-ness
Revise README to reflect version 3-ness

Shuffle things around and mention the new maintainers.

fukayatsu/redcarpet,vmg/redcarpet,JuanitoFatas/redcarpet,liquorburn/redcarpet,Hacker0x01/redcarpet,Hacker0x01/redcarpet,be9/redcarpet,Hacker0x01/redcarpet,increments/greenmat,kattybilly/redcarpet,gitcafe-dev/redcarpet,vmg/redcarpet,be9/redcarpet,liquorburn/redcarpet,Hacker0x01/redcarpet,increments/greenmat,kaneshin/redcarpet,increments/greenmat,vmg/redcarpet,emq/redcarpet,emq/redcarpet,fukayatsu/redcarpet,fukayatsu/redcarpet,kattybilly/redcarpet,kattybilly/redcarpet,emq/redcarpet,be9/redcarpet,kattybilly/redcarpet,liquorburn/redcarpet,increments/greenmat,kaneshin/redcarpet,be9/redcarpet,gitcafe-dev/redcarpet,JuanitoFatas/redcarpet,JuanitoFatas/redcarpet,kaneshin/redcarpet,gitcafe-dev/redcarpet,emq/redcarpet,kaneshin/redcarpet,vmg/redcarpet,fukayatsu/redcarpet,liquorburn/redcarpet