Rename aux files

[FredSchuller]

Updated name of L2 AUX files to solo_ANC_stix-asp-ephemeris*

[samaloney]

Looks good to me but should prob wait for @nicHoch too

[FredSchuller]

Sure, makes sense. I'll be off until Sept. 2nd but please proceed :-)

[FredSchuller]

Note that function stx_get_ephemeris_file will now look for files with name 'stix-asp-ephemeris.fits' and that will only work once the files have been updated on the data server.

[samaloney]

I guess this can be finalised now the the SOAR has accepted our test file @nicHoch?

Would it be hard to support the older name too, at least for a while?

[FredSchuller]

so should I change the way stx_get_ephemeris_file works so that it looks for the new names and then for the old ones if nothing found?

[FredSchuller]

@samaloney @ennosigaeus
I just created a new PR (#228) that includes all changes, also making things compatible with the previous AUX filenames.
Since I was about to generate a big mess when trying to include the recent changes, I preferred to start again from the up-to-date i4Ds/master branch and make only the necessary changes. Therefore PR #221 should simply be trashed...