Using gridpicker for icons (#365)

* Use the grid picker custom field for show icons

theme/style.less

@@ -85,6 +85,15 @@ span.blocklyTreeLabel {
     &:extend(.pink all);
 }
 
+/* Blockly Field: Grid picker */
+.blocklyGridPickerTooltip {
+    padding: 3px 5px;
+    background-color: #fefefe;
+    border: black solid 3px;
+    color: black;
+    border-radius: 10px;
+}
+
 /*******************************
              Monaco
 *******************************/