#4 Satellites under cutoff are not plotted

[Eugenio Realini]

Since the introduction of the function init_positioning() with version 0.3.0 beta, satellites lower than the elevation cutoff are not plotted anymore on the skyplot. In the earlier versions they were plotted as magenta dots. The reason is that init_positioning() gives in output only satellites that are above the cutoff, therefore the data about low satellites do not reach the skyplot functions.