Update the ARCHITECTURE document
Update the ARCHITECTURE document

Also has a pretty line diagram

shsmith/electrumx,Crowndev/electrumx,Groestlcoin/electrumx-grs,erasmospunk/electrumx,thelazier/electrumx,erasmospunk/electrumx,Groestlcoin/electrumx-grs,thelazier/electrumx,shsmith/electrumx,Crowndev/electrumx,bauerj/electrumx,bauerj/electrumx