Texture: Re-factor resize method (almost working)
Texture, Sprite: Remove resize (stretch) method

* This method is now obsolete with built-in SDL2 functionality
Texture: Update a few documentation comments
Texture: Relocate ResizeAlgorithm enum

* Relocating to inside Texture class in order to help avoid future
namespace collisions
Renderer: Rename logical_resolution methods

* logical_resolution -> logical_size
* set_logical_resolution -> set_logical_size
Introduce new container class: RendererInfo
Window: SDL2 implementation of bits_per_pixel
Window: Remove getDisplayPitch & pixels methods

* Our Renderer class already implements pixels
* Obtaining window pixel pitch is not necessary at this time for me