AE: Fix ExportPulse so that it tries to get the noise from SetupNavigator with an IDs::channel rather than a bankname
AE: Set the limits back to something sensible on the 2D InvestigateParameters plot
AE: Make sure that if we use n_sigma that all the channels use the slow pulse finder (simple amplitude threshold cut). We also now use the slow pulse finder for the silicon fast channels. Finally, the parameters have been optimised for all the silicon channels (see issue #184)