qmlui: fix meshes path on Windows
qmlui: fix meshes path on Windows

An extra slash doesn't bother linux, but Windows needs it

plugz/qlcplus,plugz/qlcplus,sbenejam/qlcplus,plugz/qlcplus,sbenejam/qlcplus,sbenejam/qlcplus,kripton/qlcplus,mcallegari/qlcplus,kripton/qlcplus,sbenejam/qlcplus,mcallegari/qlcplus,plugz/qlcplus,kripton/qlcplus,plugz/qlcplus,sbenejam/qlcplus,kripton/qlcplus,sbenejam/qlcplus,plugz/qlcplus,sbenejam/qlcplus,mcallegari/qlcplus,plugz/qlcplus,mcallegari/qlcplus,kripton/qlcplus,kripton/qlcplus,kripton/qlcplus,mcallegari/qlcplus,mcallegari/qlcplus,mcallegari/qlcplus