fix double negation in README, fixes #154
fix double negation in README, fixes #154

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