renamed IsQuasiHomogeneous -> IsEulerHomogeneous
code cleanup
renamed R!.DerMinusLogModule -> R!.DerModule
cleanup in DerMinusLogInWeylAlgebra
declared and installed DerMinusLogMap for [ IsDivisor, IsInt ]

+ this method sets the twists properly
+ DerMinusLogMap for [ IsDivisor ] is now a special case
whitespace
added unused declaration DerMinusLogMap for [ IsDivisor, IsList ]

as warning:
the intersection trick does not work for multi-arrangements!
declared and installed divisor attributes DerMinusLogTilde(Matrix)
used DerMinusLogTildeMatrix to simplify Annihilator1
removed obsolete code from Divisor constructor

is now taken care of in JacobiMatrix