Make transferFlags a multivariate function

It is not uncommon to transfer the flags from multiple fields to one target, e.g tansferFlags(field=["a", "b", "c"], target="x"). Currently we only support this by calling transferFlagsmultiple times, which might trash up the history with empty columns. This MR makestransferFlags` a function supporting the projection of flags from many to one.

saqc/core/translation/basescheme.py

@@ -217,7 +217,6 @@ class MappingScheme(TranslationScheme):
 
 
 class FloatScheme(TranslationScheme):
-
     """
     Acts as the default Translator, provides a changeable subset of the
     internal float flags