code: function parseRstr(rstr){
  	var startOfAssertion = rstr.indexOf('<Assertion ');
  	var endOfAssertion = rstr.indexOf('</Assertion>') + '</Assertion>'.length;
  	var token = rstr.substring(startOfAssertion, endOfAssertion);
  	return token;
  }
docs: Parses the RequestSecurityTokenResponse