Modify project selection The new project selection has two advantages: 1. It's possible to create and run e.g. projects a and aa Therefore it is possible to create a hirarchy again. 2. When inserting the project key only letters for valid projects are accepted. E.g. two projects exists aa and ab. In that case it is not possible to insert ac. Only a will be shown in the footer.

- Create empty databases from within getan.

- Create a 'Help-Widget' to give the user an information about all possible
  keys.

- reimplement RPN input for current getan implementation (28489e672e61)