Added a putContent method that allows to give strings as argument.
Added a method to create an INVALIDATE message to invalidate session keys.
Added a method to put enums as content directly to the content map.
Cleanup.
Corrected a typo.
Added possibility to invalidate the session object. This overwrites the key with zeros.
Add a class to send easily messages to other participants via HTTP. This is mainly needed from clients to server and servers to servers.
Added a class for using ExecutorService with custom interfaces (easier to use).