Rework datahandle

[Schlevidon]

Summary

Replace the datahandle with a better mechanism which would:

• Avoid unnecessary reads/writes
• Reduce coding mistakes (i.e. by ensuring that only certain types of data can be stored/retrieved)
• Generally improve performance (datahandle has to be accessed in the RHS for switch detection)

Possible Approaches

• Global function storage which stores the data as persistent variables and can be interacted with via certain commands (e.g. store x, load y, etc.)
• Replace datahandle with an instance of a handle class