* use smart pointers for almost all widget fields
* use SDL2 texture for cursor
* a lot af small tweaks and formatting
* removed CompImage class, it is actually useless as long as regular SDLImage support margins
* CGuiHandler: use smart pointers for [push|pop]Int
* Changed most gui classes to use shared pointers
* Store and use IImage as shared_ptr
* CSpellWindow redesign
* AdventureMapClasses cleanup
* CLabel: store background as smart pointer
* Store CObjectList items as smart pointers
* Removed destroy function of list item
* Store toggle buttons as smart pointers
* Use CComponent as smart pointer
* Attempt to fix artifact merchant drawing
Bonus * -> std::shared_ptr<Bonus>
This cures the following problems:
1) Memory corruption at exit. Some Bonus-es were deleted twice (mods?).
2) Memory leaks. Some Bonuses were not deleted.
3) Reduce the number of "Orphaned child" messages.
Valgrind reports 0 leaked memory now and no invalid reads/writes.
