Allow the GC to cleanup unused objects.
Allow the GC to cleanup unused objects.

	* src/NDesk.Options/NDesk.Options/Options.cs: The Regex instance should be
	  scoped to the OptionSet instance, so that when the OptionSet is collected
	  the Regex instance can be as well.  Otherwise, the Regex will hang around
	  for the entire process lifetime, for no real purpose.

chakrit/ndesk-options-mirror,MikeJansen/NDesk.Options.StrongNamed,MikeJansen/NDesk.Options.StrongNamed,MikeJansen/NDesk.Options.StrongNamed,chakrit/ndesk-options-mirror