[IMP] Make commission feature compatible with

all parsers (not only generic_csvxls_so) + male it compatible with split_counterpart option

account_move_base_import/parser/generic_file_parser.py

@@ -26,6 +26,8 @@ class GenericFileParser(FileParser):
         # set self.env for later ORM searches
         self.env = journal.env
         super().__init__(journal, ftype=ftype, extra_fields=conversion_dict, **kwargs)
+        self.commission_field = "commission_amount"
+        self.commission_sign = "-"
 
     @classmethod
     def parser_for(cls, parser_name):