gui_toolkit 0.36.1

Added

• Box_Flag.Scrollbar_Left (ui/scrollbar.odin, ui/events.odin): the overlay scrollbar of a .View_Scroll_Y box sits at its left edge instead of its right one (drawn, hit and dragged there; its grab margin widens toward the content). A panel docked on the left whose right edge joins the content (a tab sidebar whose current tab flows into the page) keeps its scrollbar on the outside. Test: tests/ui_robust scrollbar_on_the_left.