- new typed helper, WindowList_Create, to create a window list
- new service, WindowList_Destroy, to destroy a window list
- internal windowlist.cpp implementation rewritten to LIST<>

git-svn-id: http://svn.miranda-ng.org/main/trunk@7823 1316c22d-e87f-b044-9b9b-93d7a3e3ba9c