split Reiffen_data.g from Reiffen.g and call the former in examples/doc/*.g
several methods now accept defining equations in the base ring

+ NumeratorOfDifferentialAction
+ AnnihilatingOperators

simplified doc files accordingly
order now is the first argument in operations involving differentiation

. NumeratorOfDifferentialAction
. CoefficientsOfAnnihilatingOperators
. AnnihilatingOperators
. BasisOfAnnihilatingOperators
. Annihilator
. AnnihilatorOfPower