Auto detect version and view gamesesotericsoftware spine file.

This is my rewrite of kiletw/SpineViewerWPF tool with following changes:

• Use craftworkgames/MonoGame.WpfCore
• Auto read spine file version
• Fix memory leak by releasing texture when open a new file.
• Remove global variables

• This doesn't have capture image or video like SpineViewerWPF.