In `vulture::Rectangle`:
  fixed:
    types of `width, and height`
    constructor types
  added:
    constructor `(point, size)`
    `{position, size}` getters
In `graphics::Drawer`:
  fixed:
    now is class, not struct;
    texture method arguments types
In `graphics::Texture`:
  fixed:
    `size()` -> now: virtual, but not abstract;
  added:
    protected `size()` setter;
    protected `_size` field
definitions and fixes
Definitions of accessors.