Implemented SignatureMessage in FF plugin.

Currently, no verification is done, as I'm still thinking about how to
best remove the signature message from the complete message.
Added offset and length field to SignatureMessage

In order to do verification, we just splice the Signature message from
the complete message, and verify that.
Untested version of signature verification code.

Test with new server!
Added some more files to gitignore.
Added signature message case for certVerifyCallback.

Signature is ignored, but plugin works with new version of Server.

TODO: Implement signature logic.
Whitespace fixes for verifyCert.jsp
Made decryption of hash work.

RSA decryption now outputs a correct decrypted signature block, due to
it containing the correct padding and hash algorithm identification. However, hash calculation using Crypto-JS as well as hex-encoding the decrypted hash is still broken.
Verification working with firefox plugin.

RSA code is terrible, but works.
Dialogs now working correctly.
Merge branch 'ffplugin-signature'