Menus: Remove background member variable as it is already in Menu base class
AStar(Close)Container: have an unimplemented copy constructor

The classes AStarContainer and AStarCloseContainer did not have copy
constructors, which is recommended since the classes contain pointers
to allocated memory.

Signed-off-by: Stefan Beller <stefanbeller@googlemail.com>
Merge pull request #771 from stefanbeller/master

Small code cleanups