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/corelib.otmod

@@ -0,0 +1,21 @@
+Module
+  name: corelib
+  description: Contains core lua classes, functions and constants used by other modules
+  author: OTClient team
+  website: www.otclient.info
+  reloadable: false
+
+  @onLoad: |
+    dofiles 'ext'
+    dofiles 'math'
+
+    dofile 'const'
+    dofile 'util'
+    dofile 'globals'
+    dofile 'settings'
+    dofile 'keyboard'
+    dofile 'mouse'
+
+    dofiles 'ui'
+    dofiles 'widgets'
+