browser/Makefile, jshintrc add path to jshint config

We don't want our jshint runs to depend on the user's local
configuration, so passing a fixed file will give us consistent results.

Closes #2272

browser/Makefile

@@ -7,5 +7,5 @@ icons:
 	$(MAKE) -C css/icons
 
 quality:
-	jshint js/*.js
+	jshint --config jshintrc js/*.js
 .PHONY: all germline icons

browser/jshintrc

+{
+    "asi"   : true
+}