BooleanGB contains an optional strategy for doing all gb's over rings from a
certain class.  This should be done by:

	- at polynomial ring creation time, registering the strategy name
          (symbol) in the ring where gb can find it and use it
	- letting the strategy be inherited by quotient rings of the ring, but
	  not by polynomial rings over the ring
	- letting gb accept the strategy name, too

Use Strategy or Algorithm ??
