Refactored to allow hotseat and multiplayer. TODO: Create interface class for webrtc/enet multiplayer

Testbed/UIBlur.gdshader

@@ -0,0 +1,9 @@
+shader_type canvas_item;
+
+uniform float lod: hint_range(0.0, 5.0) = 0.0;
+uniform sampler2D SCREEN_TEXTURE: hint_screen_texture, filter_linear_mipmap;
+
+void fragment() {
+	vec4 color = texture(SCREEN_TEXTURE, SCREEN_UV, lod);
+	COLOR = vec4(color.rgb, 1.0);
+}