Allow setting a custom session name

[jthoward64]

An idea of what I mean in #45

This is a draft as I have not tested it, I don't see why it wouldn't work, but just to be sure.

Thid PR includes adding a way for a client to indicate how their should be named. This behavior is only enabled if the allowCustomName config is set to true. I did not add to the configuration page so the config would have to be set in the config.php file.