changed output file for cross-correlation and lag spectra. modified error...

I changed output file for cross-correlation and lag spectra: it saves now also energy and Delta_energy columns. I modified error computations using the trimmed mean for CC/lag/PF spectra, harmonic amplitudes and phases. Trimmed std are computed for both side of the distribution (left and right tails). Trimmed limit values are intended as percentage with respect to the tails distributions (eg 0.05 means that the 5% percent of the tails are not used for standard deviation computations). it is possibile to give different low/high limit values for CC and lag spectra. defaults set to 0.1 for both sides the low/high limits are set to be the same in the other cases. defaults set to 0.0. Some function comment strings modified. I added the **kwargs option at the end of some functions to pass them the possibility to use trimmed std (it works, but I do not know if this is in general ok).

-- Still to be done: change from simple means to trimmed means value, in order to be consistent