Created AbstractAlgorithm for pathfinding.

This class can be used as an interface for pathfinding algorithms.
Created class Coordinates.
Added Board::getSquare(Coordinates) method.
Created Path class for pathfinding.
Added empty classes for the A* algorithm.
Fixed AbstractAlgorithm.

- Methods are now public.
- Using qrw::Coordinates rather than integers for start and end points.
Set up basic methods and attributes for AStar.
Added qrw::Coordinates::PtrCompLess for pointer comparision.

This struct can be used to order Coordinates* in a std::set.
Added Unit::canWalkSquare() method.
Added test for Coordinates::PtrCompLess to ensure std::set compatibility.
Made qrw::Coordinates immutable.
qrw::AStar now sorts it's temporary lists with qrw::Coordinates::PtrCompLess.
Brutally forced qrw::AStar privates to public in AStarTest.
Implemented qrw::AStar::clear() which cleans up working stuff.
Added test for standard copyctor for qrw::Coordinates.

This sounds stupid but ensures that an replacement of a copy constructor does not break compatibility with qrw::AStar which needs to copy coordinates.
Implemented qrw::Coordinates::operator==().
Added qrw::AStar dtor.
Implemented basics for AStar::getPath().

This includes precondition checks and return of an Path pointer on success. The acutal logic is still missing.
Added missing tests to CPPUNIT.
Created Node class which is used by the AStar algorithm.