load the compatibility library from the correct version of pdf.js

services/web/app/views/project/editor.jade

@@ -125,6 +125,7 @@ block content
 	if usePdfNG
 		script(type='text/javascript').
 			window.requirejs.paths['libs/pdf'] = 'libs/pdfjs-1.0.712/pdf'
+			window.requirejs.paths['libs/compatibility'] = 'libs/pdfjs-1.0.712/compatibility'
 
 	script(
 		data-main=jsPath+"ide.js",