Add display of sat names in rfplot and rffit

[MartinHerren]

Hej Cees !

This PR adds the sat names in rfplot (in the plot as well as in the list of ids) and rffit.

In the identified satellites list the name will always be shown in both rfplot and rffit when the name is available in the catalog. In rfplot's plot, it is not shown by default. It can be activated either by

• pressing the n key which toggles the display of the name on and off
• giving the -n parameter at command line

Example of rfplot's window:

This PR is based on https://github.com/cbassa/strf/pull/54 (and thus also on https://github.com/cbassa/strf/pull/52 and https://github.com/cbassa/strf/pull/48) so should not be merged before they are merged.