Dev 3.0.0 - Set/get Catspeak function self/global

[katsaii]

Adds the following methods to compiled Catspeak functions:

• .getSelf() - Returns the self defined by setSelf, or the global context if none exists.
• .setGlobals(struct_or_instance) - Sets the underlying global struct to use.
• .getGlobals() - Returns the global struct defined by setGlobals.