STYLE: Adds comments in geometry module

Base/Geometry/Analytic/imstkCube.h

Base/Geometry/Analytic/imstkPlane.h

Base/Geometry/Analytic/imstkSphere.h

Base/Geometry/Map/imstkGeometryMap.h

Base/Geometry/Map/imstkIdentityMap.h

Base/Geometry/Map/imstkIsometricMap.h

Base/Geometry/Map/imstkOneToOneMap.h

Base/Geometry/Mesh/imstkHexahedralMesh.h

Base/Geometry/Mesh/imstkMesh.h

Base/Geometry/Mesh/imstkSurfaceMesh.h

Base/Geometry/Mesh/imstkTetrahedralMesh.h

Base/Geometry/Mesh/imstkVolumetricMesh.h

Base/Geometry/Reader/imstkMeshReader.h

Base/Geometry/Reader/imstkVTKMeshReader.h

Base/Geometry/imstkGeometry.h