change the behavior of the quad function.

The current definition of the quad function states that if there are 12 arguments, only the first 8 are used to specify the coordinates. 
I don't think this is the intended behavior, so I suggest changing it. 
It's easy to do, and it seems to be enough to remove the equals sign from the inequality sign.

Author: inaridarkfox4231

src/core/shape/2d_primitives.js

@@ -532,7 +532,7 @@ p5.prototype.quad = function(...args) {
   p5._validateParameters('quad', args);
 
   if (this._renderer._doStroke || this._renderer._doFill) {
-    if (this._renderer.isP3D && args.length <= 12) {
+    if (this._renderer.isP3D && args.length < 12) {
       // if 3D and we weren't passed 12 args, assume Z is 0
       this._renderer.quad.call(
         this._renderer,