Support moving nodes and refactor to eliminate recursion

[serges147]

• Fix for issue Refactor to eliminate recursion #13
• Added new postOrderTraverse method
• Reduced a bit code duplication at const vs non-const traversal algorythms - now single traverseXxxOrderImpl covers these 2 almost identical cases.
• Make nodes movable
• Rename traverse → traverseInOrder; added new traversePostOrder.

[pavel-kirienko]

Looks good. I would reduce blank lines in the implementation to maintain style consistency.

[pavel-kirienko]

Please tag a new major release afterward.

[pavel-kirienko]

• I want to simplify the remove methods (both overloads) such that they don't accept the root pointer reference anymore, because this is already available in the node itself. I think this should be a trivial change. NB: search cannot be simplified in this fashion because it doesn't take an explicit node as a parameter and it may be invoked on an empty tree.

• Consider adding root pointer invariant checks when the tree is mutated. We know that for any valid node, the root pointer pointer is never null.

• There is a minor style nit I left an in-place comment about.

Please merge and release v3 afterward. This is a very useful change because it will also allow us to save memory in another project.

[pavel-kirienko]

But wait, there's more! We can't trivially move the tree class anymore:

cavl/c++/cavl.hpp

Line 749 in 7b054aa

/// Trees can be easily moved in constant time. This does not actually affect the tree itself, only this object.

We must traverse the entire tree updating the root pointer pointer in every node. That should be easy, can you please add it?

[serges147]

But wait, there's more! We can't trivially move the tree class anymore:

cavl/c++/cavl.hpp

Line 749 in 7b054aa

/// Trees can be easily moved in constant time. This does not actually affect the tree itself, only this object.

We must traverse the entire tree updating the root pointer pointer in every node. That should be easy, can you please add it?

Yes, you are right - I've missed this :(