Version 3.0.0

Release for the 3.0.0 version of Godot Retro.
-Added new NTSC shaders and Jpeg Compression shaders! (now, in total, there are 18 shaders)
-Rewrote some of the shaders!
-New default configuration for all the shaders!
-4 new made-from-scratch example scenes!
-Removed bugs

Have fun :)!!