new 'random.update' parameter for the 'control' variable, in order to allow random update of personal/global best

hydroPSO: default value of the inertia weight 'IW' was changed from (linearly decreasing) IW.w= c(1.2, 0.4) to 'IW.w=1/(2*log(2))'

hydroPSO: fixed small bug related to improper PSO evolution when 'best.update==async'. source code was tidy up. Added '...'  parameter.

'c1, c2, lambda are now written only once in the 'PSO_logfile.txt' file when the time-varying option is chosen

'velocities' variable removed. Writing of 'Velocities.txt' and 'Particles.txt' files moved to the begining of the 'Particles Loop (j)' loop

 much less memory consumption for large values of 'maxit' and/or 'npart'. The files 'BestParamPerIter.txt', 'PbestPerIter.txt', and 'LocalBestPerIter.txt' are now written at the end of each iteration, and not at the end of the main algorithm

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