Changes to Version 2.0-0

    o Completely reworked version of the sem package. See CHANGES file for changes to older versions.
    
Changes to Version 2.1-0

	o Added equation-style model specification, via specifyEquations()
	
	o Fixed bug in classifyVariables() when <- (rather than ->) used in the model.
	
	o Fixed bug in vcov.sem() when the model has just one structural parameter or just one variance/covariance parameter.
	
Changes to Version 2.1-1

    o Added cfa() for compact specification of confirmatory factor analysis models.
