Implement Process IDs

[Sparen]

This issue covers the implementation of dynamically generated Process IDs for application scripts. These IDs can be used for hooking into events, to provide a standard way for application scripts to receive events.

In this scenario, each application script would be assigned a process ID on startup, and would have a single event handler with, say, EV_USER + PROCESS_ID, and an arbitrary number of values in an array. The script can process this however it wants to.

This may also provide a standard means for accessing menu inputs.