book: Feld 'start_date' + test,

line: balance-berechnung mit abstimmung gekoppelt + test,
abstimmung: start/enddatum automatisch

book.py

@@ -68,6 +68,13 @@ class Book(Workflow, ModelSQL, ModelView):
         states=STATES, depends=DEPENDS+['company'])
     number_atcheck = fields.Boolean(string="number when 'Checking'",
         help="The numbering of the lines is done in the step Check. If the check mark is inactive, this happens with Done.")
+    start_date = fields.Date(string='Initial Date', required=True,
+        states={
+            'readonly': Or(
+                STATES['readonly'],
+                Bool(Eval('lines')),
+                ),
+        }, depends=DEPENDS+['lines'])
     start_balance = fields.Numeric(string='Initial Amount', required=True,
         states={
             'readonly': Or(
@@ -146,6 +153,13 @@ class Book(Workflow, ModelSQL, ModelView):
     def default_company():
         return Transaction().context.get('company') or None
 
+    @classmethod
+    def default_start_date(cls):
+        """ today
+        """
+        IrDate = Pool().get('ir.date')
+        return IrDate.today()
+
     @classmethod
     def default_state(cls):
         return 'open'