Replace inline JS gtoggles with html attributes and some global JS

End goal is to remove all inline JS, starting with onclick

design/views/generic/reply/staffpm.php

@@ -22,6 +22,6 @@
 
         <input type="button" value="Preview" class="hidden button_preview_<?=$TextPrev->getID()?>" />
         <input type="submit" value="Send message" />
-        <input type="button" value="Hide" onclick="$('#compose').gtoggle(); return false;" />
+        <input type="button" value="Hide" toggle-target="#compose" />
       </form>
     </div>

static/styles/global.css

@@ -96,6 +96,10 @@ div.collage_image {
   width: 20%;
 }
 
+[toggle-target] {
+  cursor: pointer;
+}
+
 button, input[type=button], input[type=submit] {
   cursor: pointer;
   background: #fff;