Create basic framework

Signed-off-by: Justin Georgi <justin.georgi@gmail.com>

includes/GlModelViewer.php

@@ -0,0 +1,24 @@
+<?php
+
+class GlModelViewer extends ImageHandler {
+  public static function onMimeMagicInit(MimeAnalyzer $mime) {
+    $mime->addExtraTypes('application/gltf glb gltf');
+    $mime->addExtraInfo('application/gltf [DRAWING]');
+  }
+
+  public static function onMimeMagicImproveFromExtension( MimeAnalyzer $mimeAnalyzer, $ext, &$mime ) {
+	  if ( $mime !== 'application/gltf' && in_array( $ext, ['glb', 'gltf'] ) ) {
+		  $mime = 'application/gltf';
+	  }
+  }
+
+  function doTransform($image, $dstPath, $dstUrl, $params, $flags = 0) {
+  }
+
+  public static function onBeforePageDisplay(OutputPage $out) {
+    if (strpos($out->getHTML(), 'class="glmv-viewer') !== false) {
+      $out->addModules('ext.glmv');
+    }
+  }
+
+}