Have "measuring.moments_enhanced" fill an array with " deconv_imposs = ierr" #150

Currently, measuring.moments_enhanced fills a computed_moments array of floats of shape (number_of_sources, 2, 10) with source parameters and their errors.

The number of elliptical axes (default = 2) that could not be deconvolved from the clean beam is set in these lines:

    rmaj, rmin, rpa, ierr = deconv(fmaj, fmin, fpa, cmaj, cmin, cpa)
    # This parameter gives the number of components that could not be
    # deconvolved, IERR from deconf.f.
    deconv_imposs = ierr

but deconv_imposs does not end up in any array while users may want to retrieve this information.

It does not seem logical to expand the shape of computed_moments, since computed_moments contains source parameters and their corresponding errors, while deconv_imposs does not have an error.

Perhaps measuring.moments_enhanced should fill a dedicated 1-D array of size number_of_sources.