Fixed hoveredComponent being kept if mouse was going out of the
container
Fixed Anchor being reset when setting position
Fixed setHovered and setFocused being called even if visibility didn't
change
Added getter for IIcon and ItemStack
Removed the need of unique container inside screen.
Added handling of relative to parent sizes with negative width and
height
Updated comments
Changed constructors to make the parameless the default one
Changed order of methods
Updated comments
Fixed anchor position
Changed ClickEvent name
Replaced ValueChanged by CheckEvent
Added possibility to use background color for UIWindow
Changed order of methods
Updated comments
Refactored UITab and UITabGroups. Allowed tabs for UIWindows
Removed TabShape
Upadted Gui textures to add tab icons