World size passed to Render in constructor
Renamed one function in World class
Pointers to classes modified to be pointers to const
Improved units select / deselect actions

Modified:
- units selecting actions in User
Printing units health bar

Added:
- drawing health bar above Things

Removed:
- some const pointers
Fixed health bar of Things and frame drawing

Added:
- status bar chenges length according to health level
Some changes for debug tests
Variable packed into structures

Added:
- structures to put variables together