Windows (win32) Support

Added Shell usage to open files externally in their default application.
Added switch entry for windows to use shell.
Tested multiple files/file types and working on Windows 8.1.
Note: The use of shell may be possible for all operating systems, effectively removing the need for the switch, will have to be tested on other operating systems.
Merge pull request #3 from olinksoftware/patch-1

Windows (win32) Support