Added Diffie-Hellman to crypto blocks

src/avatartranslator/toproverif/AVATAR2ProVerif.java

src/proverifspec/ProVerifEquation.java

src/proverifspec/ProVerifPiSyntaxer.java

src/proverifspec/ProVerifPitypeSyntaxer.java

src/proverifspec/ProVerifSyntaxer.java

src/tmltranslator/toproverif/TML2ProVerif.java

src/ui/AvatarMethod.java