Update User Project following Force restructure in https://github.com/Chaste/Chaste/issues/417

[jmosborne]

Update the forces according to Chaste/Chaste#513

Specifically do the folllowing:

1. Replace #include "GeneralisedLinearSpringForce.hpp" with #include "LinearSpringForce.hpp" (mesh-based) or #include "PathmanathanInteractionForce.hpp" (node-based)
2. Replace MAKE_PTR(GeneralisedLinearSpringForce, ...) with MAKE_PTR(LinearSpringForce, ...) for MeshBasedCellPopulation simulations
3. Replace MAKE_PTR(GeneralisedLinearSpringForce, ...) with MAKE_PTR(PathmanathanInteractionForce, ...) for NodeBasedCellPopulation simulations