#262 jalopy
 #262 the combobox shows the year 0 to the current year
 #262 added two radiobuttons to the search dialog

The user can choose with the radiobuttons if the found stadtbildserie
should contain all or only one of the selected Suchworte. Therefore the
search statement had to be modified.
 #262 fill the combobox with the minimal year

Instead of filling the combobox from 0 to the current year. The earliest
year gets fetched in the database and now the combobox gets filled from
the earliest year to the current year.
Merge branch 'feature/262-Changes-in-the-Stadtbildsuche' into dev