Change the return type of the get method

	* The intented return type was SDL_Surface*, not a copy of this
object
Introduce a type definition 'SharedPtr'

	* Purely for convenience & readability sake
Use nom::Image class for loading the window icon

	* The original icon loading code was temporary, as the Image class
was not yet ready for using here.
Add missing header file for nom::Point2 class & rename get_position
Comment out a few SDL1 methods

	* These methods have an unclear future, so until things are
figured out... they will serve as silent reminders!
Re-implement SDL1 methods with SDL2 equivalents

- Obligatory renames
	* getDisplayFlags -> window_flags
	* getDisplayPixelsFormat -> pixel_format
	* getDisplayBounds -> display_bounds
Clean up fullscreen method

	* Remove non-functioning positioning code
	* Remove commented out SDL1 code for the method
Change return type of window_id method to uint32

	* Matches the internal SDL2 data type
Introduce several new methods into the class

	* Perhaps the most important of which is the set_active, context &
set_context methods; this, I think, may well be the solution I was
looking for in dealing with the necessity of a context before using
rendering calls such as the SDL_CreateTextureFromSurface function.
Fix the rendering issues seen by my testing on Windows platform

	* Both platforms render the windows in the same relative
positions now; all on the primary display index / monitor.
Clarify what the second integer on the application's window title is

	* Add "Display" to the string before printing the window's display ID