Refactoring

[ViPErCZ]

• async loading assets + draw preloader
• add scene object, timer object
• individual objects at a relative distance from the center - for example, a lamp and its fire -> movement in space with the lamp automatically holds the position of the fire as well
• all class using modern pointers (shared_ptr, unique_ptr etc.)
• global directional, spot and point lights by scene
• fix plane shadows (across the entire surface)
• extend animation player (example... coin rotation via animation player)
• gizmo, mark ring and better positioning objects into scene (for scene creating)
• more physics... for example jumping a snake over a chasm
  ... and more