Add a ScummVM specific overlay to be used in conjunction with touchscreen emulated mouse.

This adds on screen buttons for select, start and retroarch GUI toggle

gamepads/scummvm/scummvm_mousemode.cfg

@@ -0,0 +1,29 @@
+overlays = 2
+
+overlay0_full_screen = true
+overlay0_normalized = true
+overlay0_name = "hide"
+overlay0_range_mod = 1.5
+overlay0_alpha_mod = 2.0
+
+overlay1_full_screen = true
+overlay1_normalized = true
+overlay1_name = "landscape"
+overlay1_range_mod = 1.5
+overlay1_alpha_mod = 2.0
+
+overlay0_descs = 1
+overlay0_desc0 = "overlay_next,0.95,0.05,radial,0.015,0.025"
+overlay0_desc0_overlay = next.png
+overlay0_desc0_next_target = "landscape"
+
+overlay1_descs = 4
+overlay1_desc0 = "start,0.84,0.05,rect,0.025,0.027"
+overlay1_desc0_overlay = start.png
+overlay1_desc1 = "select,0.77,0.05,rect,0.025,0.027"
+overlay1_desc1_overlay = select.png
+overlay1_desc2 = "menu_toggle,0.90,0.05,radial,0.015,0.025"
+overlay1_desc2_overlay = rgui.png
+overlay1_desc3 = "overlay_next,0.95,0.05,radial,0.015,0.025"
+overlay1_desc3_overlay = next.png
+overlay1_desc3_next_target = "hide"