Clean up Firefox-specific code
Clean up Firefox-specific code

DoNotUseThisCodeJUSTFORKS/cryptocat,arno01/cryptocat,DoNotUseThisCodeJUSTFORKS/cryptocat,Raynes/cryptocat,DoNotUseThisCodeJUSTFORKS/cryptocat,Raynes/cryptocat,wakermahmud/cryptocat,Cryptodog/cryptocat,wakermahmud/cryptocat,arno01/cryptocat,DGO143/cryptocat,Cryptodog/cryptocat,PeterDaveHello/cryptocat,PeterDaveHello/cryptocat,Raynes/cryptocat,DGO143/cryptocat,DGO143/cryptocat