Updated deprecated CPanel calls (#2184) * Made NumSlider automatically pick the convar value. * Added PropSelect method to controlpanel. * Replaced "AddControl" with non-deprecated code. * Added dedicated method to select rope material. * Various fixes to suggestions * Minor changes * Minor clean ups * Fix Balloon tool having broken model selector * More cleanups * Added ControlPanel:ComboBoxMulti --------- Co-authored-by: Rubat <3299036+robotboy655@users.noreply.github.com>