Marble: Backport all relevant fixes for the Tour and Bookmarks to stable

completed by: Mikhail Ivchenko

mentors: Dennis Nienhüser, shentey, Sanjiban Bairagya, Torsten Rahn

 During GCI several fixes in terms of functionality and crashes have been created.

Please backport all relevant changes to the latest stable version of Marble (e.g.   remotes/origin/Applications/14.12 and  remotes/origin/KDE/4.14 ).

The backports should not introduce new functionality. The backports should only fix

- crashes

- and functionality that is available via the UI but doesn't work or doesn't work properly.

 Ensure you do proper testing!