Update to version 5.1.1

Changelog:

• wish : #1634615 get currency format from system again
• wish : #1634182 template chooser popover could be wider by default
• wish : #1629647 'Multiple Edit' to include account
• bugfix: #1638035 moving txn between account hide it into destination
• bugfix: #1637805 overwrite assignment doesnt work
• bugfix: #1635857 balance report crash when no selection in main window
• bugfix: #1635260 win: missing .dll for windows 7, vista, XP
• bugfix: #1635053 must enter Payment method twice in Add Transaction dialog
• bugfix: #1633915 win: libgnutls-30.dll missing XP, Vista, 7
• bugfix: #1633895 manage assignment display some payee instead of category