* 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--
- implemented switch in settings screen
- implemented "0 speed", animation-free. *may* also work for player-owned heroes
- removed no longer used creature window switch
- 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