Read database type from file

[olpeh]

When opening a database file, the app should read the database type from the selected file.

Case:
Was trying to open a Keepass 2 file but the type selection had Keepass 1 preselected and I did not notice it. Tried 10 times and wondered why my password was not working before realizing this.

[jobe-m]

Bugfix #10 should at least fix the other way: Opening a Keepass 1 file but type selector had Keepass 2 preselected.
After next release I will look into this again while implementing creation of a new Keepass 2 database within ownKeepass.