Perform Multi-SSA queries to an Spectral VO Service

Snippet showing how to use AstroTaverna "VO service perspective" and other tools for performing Multi-SSA queries to Spectral VO Services. The input is a VOTable with a list of source names and coordinates to perform the multi-query. Add_n_concat_tables tool is used to concatenate the list of responses issued from the multiquery. The result is a VOTable that may be renderized properly in the perspective Results, choosing Value Type as VOTable. It may also be sent via SAMP to other VO soft implementing SAMP. In this particular case, the Spectral Service queried is the "The Hubble Space Telecope Legacy Archive (HLA)"