Move the example to its own sub-folder
Improve Terrain\MyNodeTest's exception validation
Add Connections\MyNode
Add Connections\Connection
Add Graph
Rename the Connections example
Add the new Graph example to the Changelog
Add ability to get a Graph's direct successors
Add Graph\MyAStar
Fix a bug in the algorithm
Remove unnecessary step in the algorithm

The algorithm was removing a node from the open list, just to add it
afterwards. As the 'add' method replaces any node with the same ID, the
removal was not necessary.
Refactor Graph\MyAStartTest

The graph now uses an admissible heuristic.
Increase the Graph\MyAStar tests
Add Graph\SequencePrinter
Add Graph example