added number conversion in HTML value retrieval

Changes:
- number input fields now return numbers
- range elements removed since they are untested

Additions:
- added min and step specifiers to input fields associated to
  item number properties
- added a color hint for invalidity of
  item number input fields in actor sheet

src/templates/item/partials/description.hbs

@@ -13,7 +13,7 @@
         </div>
         <div class="side-property">
             <label for="data.quantity">{{localize 'DS4.Quantity'}}</label>
-            <input type="number" data-dtype="Number" name="data.quantity" value="{{data.quantity}}" />
+            <input type="number" min="0" step="1" data-dtype="Number" name="data.quantity" value="{{data.quantity}}" />
         </div>
         <div class="side-property">
             <label for="data.storageLocation">{{localize 'DS4.StorageLocation'}}</label>