* 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
* fixed displaying free upgrades
* do not try to print 3rd or more resource in slot cost (in theory possible with mods)
** we need dynamic gui for that
* CDefEssential--
- renamed CAdventureMapButton to more expectable CButton
- merged CButtonBase into CButton
- created more generic class for clickable elements
- created more generic class for selectable elements
- renamed CHighlightableButton to CToggleButton
- renamed CHighlightableButtonsGrous to CToggleGroup
- minimized differences between API of all these classes
- removed all but one contructors in buttons, with same parameters across all classes
