Add initial/basic support for "simple" mobile grid filter w/ radio buttons

so far only one such filter is (presumably?) supported..etc.

tailbone/static/css/mobile.css

@@ -34,3 +34,8 @@
     font-weight: bold;
     margin-top: 1em;
 }
+
+/* make sure space comes between simple filter and "grid" list */
+.simple-filter {
+    margin-bottom: 1.5em;
+}

tailbone/static/js/tailbone.mobile.js

@@ -69,6 +69,12 @@ $(document).on('pageshow', function() {
 });
 
 
+// handle radio button value change for "simple" grid filter
+$(document).on('change', '.simple-filter .ui-radio', function() {
+    $(this).parents('form:first').submit();
+});
+
+
 // vendor validation for new purchasing batch
 $(document).on('click', 'form[name="new-purchasing-batch"] input[type="submit"]', function() {
     var $form = $(this).parents('form');