New commands \savecaptionsetup and \restorecaptionsetup
If we append every \captionsetup argument to \caption@settings, we could easily offer \savecaptionsetup{} which will simply save \caption@settings to \caption@settings@, and \restorecaptionsetup{} which will simply restore the default settings and execute \captionsetup with the stored values afterwards.
Furthermore \setcaptiontype could be improved this way: If \caption@saved@settings isn't defined, save \caption@settings to \caption@saved@settings. Otherwise restore the saved settings before applying the type. This way a \captionsetup{table} within a figure would not extend the "figure" settings but switch to "table" settings instead.
Edited by Axel Sommerfeldt