updated translation
Merge branch 'master' of https://github.com/20centaurifux/Bookkeeping
added database revision & upgrade utility
removed debugging message
added new table for storing exchange rates
added new exchange rate related methods to data provider interface
added exchange rate methods to SQLiteProvider
implementation of ExchangeUtil class
updated transfer dialog: amount is exchanged now
updated translation
added currency to Template class
GUI update: currency support for templates