Theme: Show the stringified app version rather than the major version.

This was a regression, we changed that by accident in 1.6.0.

(cherry picked from commit 760ecd71fc48c9d8a3e825273bcc325b35c4be65)
Fix a possible crash caused by a dangling pointer
FolderWizard: Get folder map from FolderMan rather than store locally.

If the Folder::Map object is kept locally in the wizard, changes to
the map are not reflected there, as they happen when signing out.
This fixes bug #1875
Add missing cmakedefine for HAVE_ASPRINTF and minor cleanup.

Fixes windows build.
Merge remote-tracking branch 'origin/1.6'