Tables: Made only first column honor Indent by default (like Columns api) and exposed flags. Added simple Tree demo.

imgui_internal.h

@@ -1908,6 +1908,7 @@ struct ImGuiTable
     ImU32                       BorderColorLight;
     float                       BorderX1;
     float                       BorderX2;
+    float                       HostIndentX;
     float                       CellPaddingX1;              // Padding from each borders
     float                       CellPaddingX2;
     float                       CellPaddingY;