Updated README to be more clear about which RFCs are supported.
Updated README to be more clear about which RFCs are supported.

iainbeeston/addressable,EiNSTeiN-/addressable,Hacker0x01/addressable,107191613/addressable,shaicoleman/addressable,sporkmonger/addressable,rkh/addressable,sferik/addressable,davidbegin/addressable