feat(implicitTiling): Add support for external buffer (#1038)

* fix(implicitTiling): Ignore external buffer

* feat(implicitTiling): support external buffer

* feat(implicitTiling): reformat the code

* Remove __basePath reference from SUBTREELoader

* Fix async parseTile

* Remove outdated comment

---------

Co-authored-by: Garrett Johnson <garrett.kjohnson@gmail.com>

Author: AnthonyGlt

src/plugins/base/ImplicitTilingPlugin.js

@@ -41,13 +41,13 @@ export class ImplicitTilingPlugin {
 
 	}
 
-	parseTile( buffer, parseTile, extension ) {
+	parseTile( buffer, tile, extension ) {
 
 		if ( /^subtree$/i.test( extension ) ) {
 
-			const loader = new SUBTREELoader( parseTile );
-			loader.parse( buffer );
-			return Promise.resolve();
+			const loader = new SUBTREELoader( tile );
+			loader.workingPath = tile.__basePath;
+			return loader.parse( buffer );
 
 		}