change CODE URL from FTP to HTTP

See issue report on the old prefactor github page: https://github.com/lofar-astron/prefactor/issues/297

as well as commit to master: https://github.com/lofar-astron/prefactor/commit/73809818e7cfac171ce91a12024b7ca10552eee2

docs/source/target.rst

@@ -306,7 +306,7 @@ A comprehensive explanation of the baseline selection syntax can be found `here`
 - ``A-Team_skymodel``: location of the A-Team skymodels
 - ``target_skymodel``: location of a user-defined target skymodel used for the self-calibration
 
-*Averaging for the calibrator data*
+*Averaging for the target data*
 
 - ``avg_timeresolution``: intermediate time resolution of the data in seconds after averaging (default: 4)
 - ``avg_freqresolution`` : intermediate frequency resolution of the data after averaging (default: 48.82kHz, which translates to 4 channels per subband)