added label to trajectories (for kdv.Param)
added fluxR (instability parameter)
added fluxR to __getitem__()
correction to relative time in TLMLauncher
error correction in Trajectory.cut()
added plotPSpec to PeriodicGrid
Merge branch 'master' of uqam.martn.info:/home/martn/depotGit/pyfKdV
resolved aliasing problem with rho(x)
change tReal for tf (when t0<>0)
testGrad to 1000 nDt
rndSpecDiff sigma?
removed half precision indicator
seed=None by default in rndSpecVec

i'm not sure sig does anything...
How to produce an spectral error which
has the desired error statistics?
(in term of std)
added nDt=2000 to testGrad
added plotAll to PeriodicGrid
minor modif to plots in grid
dtStable:grid included in param
added kGrid to PeriodicGrid (spectral grid associated)
corrected for a missing /2 on rho

using the centered scheme for rho:
   A2=A0-dt*r(A2+A0)/2
=> A2(1-dt*r/2)=A0(1-dt*r/2)
             ^            ^
Trajectory.concatenate takes t0 from 1st traj (self)