Variable RNG Seed Plugin for GBStudio

Just a quick little plugin I made to expose GBStudio's built-in seeded RNG functions as an in-editor event. This should allow you to use randomization in predictable ways (as in the procedurally-generated games I'm developing).

Right now, you only have the option to select a variable to use as the seed. That's because the GBVM instruction for seeded RNG only accepts a variable ID, and I'm not confident enough in my GBVM skills to mess around with anything else.