Refactoring the mesh.

examples/heat-equation/tnl-heat-equation-eoc.h

examples/heat-equation/tnl-heat-equation.h

src/mesh/CMakeLists.txt

src/mesh/config/tnlMeshConfigBase.h

src/mesh/layers/tnlMeshStorageLayer.h

src/mesh/layers/tnlMeshSubentityStorageLayer.h

src/mesh/layers/tnlMeshSuperentityAccess.h

src/mesh/layers/tnlMeshSuperentityStorageLayer.h

src/mesh/tnlMesh.h

src/mesh/tnlMeshEntity.h

src/mesh/tnlMeshEntityInitializer.h

src/mesh/tnlMeshEntityOrientation.h

src/mesh/tnlMeshEntityReferenceOrientation.h

src/mesh/tnlMeshEntitySeed.h

src/mesh/tnlMeshEntitySeedKey.h

src/mesh/tnlMeshInitializer.h

src/mesh/tnlMeshIntegrityCheckerLayer.h

src/mesh/tnlMeshReaderNetgen.h

src/mesh/tnlMeshSubentitySeedCreator.h

src/mesh/tnlMeshSuperentityStorageInitializer.h