nsICMSMessage2 in Firefox 3.6a1pre

 Async version of nsICMSMessage::VerifyDetachedSignature.
 Code will be executed on a background thread and
 availability of results will be notified using a 
 call to nsISMimeVerificationListener.

 We are using "native unsigned char" ptr, because the function 
 signatures of this one and nsICMSMessage::verifyDetachedSignature 
 should be the identical. Cleaning up nsICMSMessages needs to be
 postponed, because this async version is needed on MOZILLA_1_8_BRANCH.

 Once both interfaces get cleaned up, the function signature should
 look like:
     [array, length_is(aDigestDataLen)]
     in octet aDigestData,
     in unsigned long aDigestDataLen);

 Async version of nsICMSMessage::VerifySignature.
 Code will be executed on a background thread and
 availability of results will be notified using a 
 call to nsISMimeVerificationListener.