[IMP] Added the voucher period computation in the account_statement_ext module while it know depends on the account_voucher module.

[MIGR] Mark the account_statement_ext_voucher as deprecated is it is no more used.

account_statement_ext/__init__.py

@@ -22,3 +22,4 @@
 import statement
 import report
 import account
+import voucher

account_statement_ext/__openerp__.py

@@ -63,6 +63,8 @@
     all the erronous line in a same popup instead of raising and crashing on every step.
 
  4) Remove the period on the bank statement, and compute it for each line based on their date instead.
+    It also add this feature in the voucher in order to compute the period correctly.
+    
 
  5) Cancelling a bank statement is much more easy and will cancel all related entries, unreconcile them,
     and finally delete them.