Use already calculated bounding box for 'maxmin' calculations.
Make dialog shifting a bit more reliable.
[QA] Fix some issues spotted with cppcheck 1.59
Fix some layer sorting issues.

Ensure waypoints get sorted upon addition.
Ensure the treeview is available before attempting to sort within it.
Fix name search using Google.

It appears some redirection now occurs, so better allow for that to happen.
More reliable waypoint symbol resetting on preferences change.

Problem introduced in commit SHA1:9e3fa3387a28bc41a34ad01394f681b5c401b1a4,
fix g_list usage otherwise doesn't do more than one layer in the list!