Fixture Manager: remove uinverses group when empty
Fixture Manager: remove uinverses group when empty

hveld/qlcplus,joepadmiraal/qlcplus,sbenejam/qlcplus,hveld/qlcplus,kripton/qlcplus,joepadmiraal/qlcplus,joepadmiraal/qlcplus,bjlupo/rcva_qlcplus,sbenejam/qlcplus,kripton/qlcplus,kripton/qlcplus,mcallegari/qlcplus,joepadmiraal/qlcplus,plugz/qlcplus,joepadmiraal/qlcplus,mcallegari/qlcplus,plugz/qlcplus,bjlupo/rcva_qlcplus,bjlupo/rcva_qlcplus,kripton/qlcplus,sbenejam/qlcplus,peternewman/qlcplus,nedmech/qlcplus,kripton/qlcplus,peternewman/qlcplus,bjlupo/rcva_qlcplus,sbenejam/qlcplus,plugz/qlcplus,hveld/qlcplus,hveld/qlcplus,sbenejam/qlcplus,mcallegari/qlcplus,hveld/qlcplus,peternewman/qlcplus,nedmech/qlcplus,nedmech/qlcplus,plugz/qlcplus,sbenejam/qlcplus,sbenejam/qlcplus,joepadmiraal/qlcplus,peternewman/qlcplus,kripton/qlcplus,mcallegari/qlcplus,peternewman/qlcplus,mcallegari/qlcplus,bjlupo/rcva_qlcplus,plugz/qlcplus,mcallegari/qlcplus,kripton/qlcplus,nedmech/qlcplus,nedmech/qlcplus,hveld/qlcplus,bjlupo/rcva_qlcplus,mcallegari/qlcplus,plugz/qlcplus,plugz/qlcplus,peternewman/qlcplus,nedmech/qlcplus