[TO-DO] Developer Commentary system that is similar to Source

[sabianroberts]

I'd like ZAMNHL to have a Developer Commentary system whereas you can place "Commentary" point entities around a map and assign them to a sound file that will only show if the client's commentary CVar value is set to 1.

If you need a reference on how the feature works, play Half-Life 2: Lost Coast (or any Source game other than Half-Life 2) with the Developer Commentary feature