[FIX] Restructure and expand tests. Fix some bugs.

There is now a common class to test import of statements and their transactions.
Fixes:
- Field in regular expression for mt940 rabo parser was to short for bank-account.
- Wrong name used for reference attribute in mt940 rabo parser;
- Attribute transferred_amount should not have been renamed amount in BankTransaction.

bank_statement_parse/parserlib.py

@@ -44,14 +44,14 @@ class BankTransaction(dict):
         self['name'] = name
 
     @property
-    def amount(self):
+    def transferred_amount(self):
         """property getter"""
         return self['amount']
 
-    @amount.setter
-    def amount(self, amount):
+    @transferred_amount.setter
+    def transferred_amount(self, transferred_amount):
         """property setter"""
-        self['amount'] = amount
+        self['amount'] = transferred_amount
 
     @property
     def eref(self):