Issue #1852692 by Marty2081, cpliakas: Fixed overridden connection parameters still used after unchecking "Modify Acquia Search Connection Parameters"

Issue #1689778 by alanmackenzie, cpliakas, Nick_vh: Added support for connecting to more than one subscription.

Issue #1619770 by cpliakas: Added default fl param as a backwards compatible change to the missing defaults in Acquia Search's solrconfig.xml file.