Change == and != to do pointer comparison on arrays and proplists (formerly === and !==). Remove === and !=== and introduce function DeepEqual for contents comparison.

There have been some bugs and crashes related to unwanted deep comparison (e.g. in the maze scenario). Scripters very rarely need deep comparison, so it should not be the default for the most commonly used operator.

This also changes behaviour of GetIndexOf to do pointer comparison.

This change has Guenther's seal of approval.
Add missing documentation for LogCallStack().