Update headers and online manual

src/colvar/Angle.cpp

src/colvar/DRMSD.cpp

src/colvar/Distance.cpp

src/colvar/MultiRMSD.cpp

src/colvar/PCARMSD.cpp

src/colvar/RMSD.cpp

src/colvar/Torsion.cpp

src/crystallization/DFSBasic.cpp

src/crystallization/DFSClusterRadius.cpp

src/crystallization/DFSClustering.h

src/crystallization/DFSMaxSize.cpp

src/crystallization/DFSNumberOfClusters.cpp

src/crystallization/Gradient.cpp

src/crystallization/GradientVessel.cpp

src/crystallization/OrientationSphere.h

src/crystallization/SMAC.cpp

src/crystallization/Steinhardt.h

src/function/Target.cpp

src/generic/DumpAtoms.cpp

src/generic/DumpDerivatives.cpp