Some more UI updates and fixes.

* Added UICreatureButton class for handling/replacing "battle buttons" (can now be used in other modules).
* Added the ability to use items on creatures via the battle window.
* Some minor cosmetics.

modules/client_skins/skins/default/styles/buttons.otui

@@ -58,4 +58,4 @@ NextButton < BrowseButton
   icon-source: /images/arrow_right.png
 
 PreviousButton < BrowseButton
-  icon-source: /images/arrow_left.png
+  icon-source: /images/arrow_left.png

modules/client_skins/skins/default/styles/creaturebuttons.otui

@@ -0,0 +1,48 @@
+CreatureButton < UICreatureButton
+  height: 20
+  margin-bottom: 5
+
+  UICreature
+    id: creature
+    size: 20 20
+    anchors.left: parent.left
+    anchors.top: parent.top
+    phantom: true
+
+  UIWidget
+    id: spacer
+    width: 5
+    anchors.left: creature.right
+    anchors.top: creature.top
+    phantom: true
+
+  UIWidget
+    id: skull
+    height: 11
+    anchors.left: spacer.right
+    anchors.top: spacer.top
+    phantom: true
+
+  UIWidget
+    id: emblem
+    height: 11
+    anchors.left: skull.right
+    anchors.top: creature.top
+    phantom: true
+
+  Label
+    id: label
+    anchors.left: emblem.right
+    anchors.top: creature.top
+    color: #888888
+    margin-left: 2
+    phantom: true
+
+  ProgressBar
+    id: lifeBar
+    height: 5
+    anchors.left: spacer.right
+    anchors.right: parent.right
+    anchors.top: label.bottom
+    margin-top: 2
+    phantom: true