Lenstool

Create an "internal check" function automatically run by lenstool with more explicit messages / warnings.

Possibility to have (optional) interaction with the user / different nivels of checks?

List of points to check (non-exhaustive):

• number of optimised z_mult vs number of multiple images without redshifts (already implemented but message should be more explicit on the non-matched systems).

• check if two images in one or several systems have exactly the same location (should not normally happen, but maybe could be override by the user?)

• redshift differences in the same system ID.

• number of lenses (nlens) vs number of potentials (Warning, re-adjustment, confirmation by the user...)

• check if some wcs coordinates are completely off the rest (fixed limit ~ 5 arcmin? or dmax?, give a warning)