hydroPSO: the convergence of the algorithm controlled by 'reltol' is now defined by 'reltol <= normalised swarm radius'

fixed bug in hydroPSO function, which was originated when 'gof.Ini' and/or 'gof.Fin' was/were not given as parameters for .model.FUN.args. See NEWS file

'sim' and 'obs' are now checked for time attributes when 'gof.Ini' and/or 'gof.Fin' is/are used. 'ChangeLog' file added