Tweak CRUD form buttons a little.

Change submit button wording for edit forms, from "Update" to "Save".  Also
show Cancel as a link instead of button.

tailbone/templates/forms/form.mako

@@ -9,7 +9,7 @@
     % if form.creating and form.allow_successive_creates:
         ${h.submit('create_and_continue', form.successive_create_label)}
     % endif
-    <button type="button" onclick="location.href = '${form.cancel_url}';">Cancel</button>
+    <a href="${form.cancel_url}">Cancel</a>
   </div>
 
   ${h.end_form()}