Fix account not selected on bank.tabjournal and date warning on journal.edit

[mladjo2505]

Closes #470

[mladjo2505]

• Talk with @hildegunn95 about how to save dates and how to show warnings on journal edit page

[mladjo2505]

When the journal's date is invalid(ex. 2016-06-31 or 2017-45-56) do not allow any save actions and alert with the message 'Journal date is invalid.'('Bilagsdato er ikke gyldig').
Also if the date is not in the journal's selected period just add a warning label next to the period dropdown, something like 'Journal period is not the same as journal date.'('Perioden er ikke lik bilagsdato.')