Packages system with .otpkg files

When otclient initializes it tries to find all .otpkg files inside the
current search paths (./ ./modules ./addons) and then add them
to the front of current search paths. This way .otpkg can contains
many modules/addons and modifications in a single file that otclient
can recognize.

otpkg files can be compressed files supported by PhysFS, which
are ZIP (.zip) and LZMA (.7z).

modules/corelib/ui/uimessagebox.lua

@@ -38,7 +38,7 @@ function UIMessageBox.display(title, message, flags)
     connect(messagebox, { onEscape = function(self) self:cancel() end })
   end
 
-  messagebox:lock()
+  --messagebox:lock()
 
   return messagebox
 end