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/corelib/ui/radiogroup.lua

@@ -0,0 +1,44 @@
+RadioGroup = newclass()
+
+function RadioGroup.create()
+  local radiogroup = RadioGroup.internalCreate()
+  radiogroup.widgets = {}
+  return radiogroup
+end
+
+function RadioGroup:destroy()
+  for k,widget in pairs(self.widgets) do
+    widget.onClick = nil
+  end
+  self.widgets = {}
+end
+
+function RadioGroup:addWidget(widget)
+  table.insert(self.widgets, widget)
+  widget.onClick = function(widget) self:selectWidget(widget) end
+end
+
+function RadioGroup:removeWidget(widget)
+  if self.selectedWidget == widget then
+    self:selectWidget(nil)
+  end
+  widget.onClick = nil
+  table.removevalue(self.widgets, widget)
+end
+
+function RadioGroup:selectWidget(selectedWidget)
+  if selectedWidget == self.selectedWidget then return end
+
+  local previousSelectedWidget = self.selectedWidget
+  self.selectedWidget = selectedWidget
+
+  if previousSelectedWidget then
+    previousSelectedWidget:setChecked(false)
+  end
+
+  if selectedWidget then
+    selectedWidget:setChecked(true)
+  end
+
+  signalcall(self.onSelectionChange, self, selectedWidget, previousSelectedWidget)
+end