Fix for weird message-ids Rated 5 out of 5 stars

Folks, I found out that some e-mail clients generate a long and weird message-id. This could impact xnote as it uses this id as the filename. So when a message-id ends up begin an invalid filename, you wouldn't be able to create an xnote on that message.
I've built a simple hack to use the md5 hash of the message-id instead as filename. It works.
If anyone is willing to test it, let me know I can send the xpi.
Just my 2c at this terrific extension.
Mail me at gramhorst a t gmail d o t com