Update gitignore

We don't have demos, tutorials, tests. And we have only one subdirectory
level under examples.

Change-Id: I62d4af4991f42b768d8e5cf9a5c2ea825b9e3588
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>
Silence some compiler warnings

Remove an implicit QString creation and remove an unused method.

Change-Id: I04511c761628511ea82275871e0fca9f692ff9c4
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>