Refactoring and flexibility changes

* Split game module into game and game_interface
* Move core_lib to corelib
* Move miniwindow to corelib
* Introduce init.lua script for initializing the client, giving much more flexibility
* OTClient is no longer Application derived and is much simpler

modules/game_interface/gameinterface.otui

@@ -0,0 +1,66 @@
+GameSidePanel < UIMiniWindowContainer
+  image-source: /images/sidepanel.png
+  image-border: 4
+  padding: 4
+
+GameBottomPanel < Panel
+  image-source: /images/bottompanel.png
+  image-border: 4
+
+GameMapPanel < UIGameMap
+  padding: 4
+  image-source: /images/mappanel.png
+  image-border: 4
+
+UIWidget
+  id: gameRootPanel
+  anchors.fill: parent
+  anchors.top: topMenu.bottom
+
+  GameMapPanel
+    id: gameMapPanel
+    anchors.left: gameLeftPanel.right
+    anchors.right: gameRightPanel.left
+    anchors.top: parent.top
+    anchors.bottom: gameBottomPanel.top
+    focusable: false
+
+  GameBottomPanel
+    id: gameBottomPanel
+    anchors.left: gameLeftPanel.right
+    anchors.right: gameRightPanel.left
+    anchors.top: bottomSplitter.top
+    anchors.bottom: parent.bottom
+
+  GameSidePanel
+    id: gameLeftPanel
+    width: 190
+    layout: verticalBox
+    anchors.left: parent.left
+    anchors.top: parent.top
+    anchors.bottom: parent.bottom
+    focusable: false
+
+  GameSidePanel
+    id: gameRightPanel
+    layout: verticalBox
+    width: 190
+    anchors.right: parent.right
+    anchors.top: parent.top
+    anchors.bottom: parent.bottom
+    focusable: false
+
+  Splitter
+    id: bottomSplitter
+    anchors.left: gameLeftPanel.right
+    anchors.right: gameRightPanel.left
+    anchors.bottom: parent.bottom
+    relative-margin: bottom
+    margin-bottom: 172
+    @canUpdateMargin: function(self, newMargin) return math.max(math.min(newMargin, self:getParent():getHeight() - 300), 100) end
+    @onGeometryChange: function(self) self:setMarginBottom(math.min(math.max(self:getParent():getHeight() - 300, 100), self:getMarginBottom())) end
+
+  UIWidget
+    id: mouseGrabber
+    focusable: false
+    visible: false