clean up README a bit; moving the bit Rationale into the github wiki
clean up README a bit; moving the bit Rationale into the github wiki

Neopallium/mailinabox,mail-in-a-box/mailinabox,PortableTech/mailinabox,jmedding/mailinabox,ianberinger/mailinabox,ianberinger/mailinabox,pichak/mailinabox,b-deng/mailinabox,m4rcs/mailinabox,mboersma/mailinabox,d5ve/mailinabox,choltha/mailinabox,PortableTech/mailinabox,ianberinger/mailinabox,mboersma/mailinabox,jjz/mailinabox,mboersma/mailinabox,brocktice/mailinabox,nstanke/mailinabox,Toilal/mailinabox,jprice/mailinabox,jprice/mailinabox,mail-in-a-box/mailinabox,mboersma/mailinabox,brocktice/mailinabox,choltha/mailinabox,m4rcs/mailinabox,hnk/mailinabox,hnk/mailinabox,choltha/mailinabox,hnk/mailinabox,b-deng/mailinabox,Toilal/mailinabox,nstanke/mailinabox,Neopallium/mailinabox,jjz/mailinabox,b-deng/mailinabox,pierreozoux/mailinabox,Neopallium/mailinabox,pierreozoux/mailinabox,mail-in-a-box/mailinabox,jjz/mailinabox,jprice/mailinabox,pichak/mailinabox,pierreozoux/mailinabox,jmedding/mailinabox,Neopallium/mailinabox,hnk/mailinabox,jmedding/mailinabox,nstanke/mailinabox,PortableTech/mailinabox,choltha/mailinabox,Toilal/mailinabox,m4rcs/mailinabox,Toilal/mailinabox,mail-in-a-box/mailinabox,b-deng/mailinabox,jmedding/mailinabox,d5ve/mailinabox,PortableTech/mailinabox,ianberinger/mailinabox,ianberinger/mailinabox,nstanke/mailinabox,d5ve/mailinabox,m4rcs/mailinabox,mboersma/mailinabox,d5ve/mailinabox,d5ve/mailinabox,pierreozoux/mailinabox,b-deng/mailinabox,Neopallium/mailinabox,nstanke/mailinabox,brocktice/mailinabox,jprice/mailinabox,brocktice/mailinabox,pierreozoux/mailinabox,PortableTech/mailinabox,jjz/mailinabox,jjz/mailinabox,jmedding/mailinabox,jprice/mailinabox,choltha/mailinabox,pichak/mailinabox,m4rcs/mailinabox,pichak/mailinabox,brocktice/mailinabox