Starting new branch "CollisionSystem" on Sprint3
Restructuring files for the exporter of the CollisionSystem.
CollisionSystem exporter: code reviewed and rewritten.
CollisionSystem exporter: code compiling. Must fix widget error.
CollisionSystem: exporter. Must fix NULL SceneNode in CollObjExporter:98 and :116
CollisionSystem exporter: successfully checked some exports.
Respective .mesh and .scene files added to repository.
Circle mesh gives error, there are too many vertex in 001_circle.mesh file.
CollisionSystem importer: interface definition.

Compiles. Must implement single function "importFromFile()"
CollisionSystem importer: code almost finished.

Must complete collision objects generation functions (CollObjImporter.cpp),
and check all functionality.

Added 001_edge.mesh. Must add reference to it in ColisionesPrueba.scene.