html-preview: fix installation of resource files to data dir

plugins/html-preview/Makefile.am

@@ -8,6 +8,10 @@ dist_plugin_DATA = html-preview.plugin
 moduledir = $(libdir)/gnome-builder/plugins/html_preview_plugin
 dist_module_DATA = \
 	html_preview_plugin/__init__.py \
+	$(NULL)
+
+resourcedir = $(datadir)/gnome-builder/plugins/html_preview_plugin
+dist_resource_DATA = \
 	html_preview_plugin/markdown.css \
 	html_preview_plugin/markdown-view.js \
 	html_preview_plugin/marked.js \

plugins/html-preview/html_preview_plugin/__init__.py

@@ -51,7 +51,6 @@ class HtmlPreviewData(GObject.Object, Builder.ApplicationAddin):
         engine = Peas.Engine.get_default()
         info = engine.get_plugin_info('html_preview_plugin')
         datadir = info.get_data_dir()
-        print ("DATA_DIR: %s\n", datadir)
         path = os.path.join(datadir, name)
         return open(path, 'r').read()