Added translation settings (change language in settings)

New:
- Settings window (so far only choosing language)
- 'settings' table with 2 rows (setting -> type of setting e.g. language, parameter1 -> data)

You have to rebuild (manually delete) your Moneychanger database to add the new settings table.

The German translations isn't finished yet because there still might happen a few changes to the UI until the first release. It's just the windows "Settings" and "Deposit" I have translated to demonstrat the changing the language works.

After changing the language you have to restart the application (info messagebox pops up).
How to for translators and maintainer