Coherent notation for departure and gradJ_o

Departure function of x not xi (B_sqrt_op is
applied before calling departure).
Also, we reverted to a previous sign convention
to fit with usual notation in the litterature:
    d(x,y)=y-H(x)
Added diagnostics to the optimization output
Removed obsolete arguments from kd_departure

some other cosmetic changes..
Reordering of pyKdV.Launcher arguments

Also, H_TL_Adj should be linearized around x(t)
and not x_b(t), which means, the gradient of the
cost function needs the model to update the
trajectory.