"Morphex's Blogologue": Thread-safe message database for SMPS

I hacked a little more on the SMPS project today, which resulted in the following commit:

https://github.com/morphex/smps/commit/8c565c561c0a9593f4d5e...

A pretty straight-forward message passing queue, that expires messages after n number of seconds. I guess the only thing left now before it can be put into practical use, is adding some sort of handshake with a secret, so that it is possible to protect the message queue from unauthorized access.