wire up touch handlers

I have no idea how events like on.touchpressed were working until now.
This still seems useful to add on.touch_press.

0001-on

@@ -13,6 +13,9 @@ on = {
   --   on.mouse_release (see love.mousereleased)
   --   on.mouse_move (see love.mousemoved)
   --   on.mouse_wheel_move (see love.wheelmoved)
+  --   on.touch_press (see love.touchpressed)
+  --   on.touch_release (see love.touchreleased)
+  --   on.touch_move (see love.touchmoved)
   --   on.keychord_press (see keychord.lua in this repo)
   --   on.text_input (see love.textinput)
   --   on.key_release (see love.keyreleased)

main.lua

@@ -200,6 +200,22 @@ function App.wheelmoved(dx,dy)
   if on.mouse_wheel_move then on.mouse_wheel_move(dx,dy) end
 end
 
+function App.touchpressed(x,y, dx,dy, pressure)
+  if Mode == 'error' then return end
+  Cursor_time = 0  -- ensure cursor is visible immediately after it moves
+  if on.touch_press then on.touch_press(x,y, dx,dy, pressure) end
+end
+
+function App.touchreleased(x,y, dx,dy, pressure)
+  if Mode == 'error' then return end
+  Cursor_time = 0  -- ensure cursor is visible immediately after it moves
+  if on.touch_release then on.touch_release(x,y, dx,dy, pressure) end
+end
+
+function App.touchmoved(x,y, dx,dy, pressure)
+  if on.touch_move then on.touch_move(x,y, dx,dy, pressure) end
+end
+
 function App.focus(in_focus)
   if Mode == 'error' then return end
   if in_focus then

reference.md

@@ -88,6 +88,21 @@ two categories.
   right. Positive values for `dy` indicate upward movement.
   (Based on [LÖVE](https://love2d.org/wiki/love.wheelmoved).)
 
+* `on.touch_press(x,y, dx,dy, pressure)` -- called when you touch a
+  multi-touch screen. Provides in `x` and `y` the point on the screen at which
+  the touch occurred.
+  (Based on [LÖVE](https://love2d.org/wiki/love.touchpressed).)
+
+* `on.touch_release(x,y, dx,dy, pressure)` -- called when you release a touch.
+  Provides the same arguments as `on.touch_press()` above.
+  (Based on [LÖVE](https://love2d.org/wiki/love.touchreleased).)
+
+* `on.touch_move(x,y, dx,dy, pressure)` -- called when you move any finger on
+  a multi-touch screen. Provides the same arguments as `on.touch_press()`
+  above, with `dx` and `dy` containing the amount moved since the previous
+  call to `touch_move`.
+  (Based on [LÖVE](https://love2d.org/wiki/love.touchmoved).)
+
 * `on.keychord_press(chord, key)` -- called when you press a key-combination.
   Provides in `key` a string name for the key most recently pressed ([valid
   values](https://love2d.org/wiki/KeyConstant)). Provides in `chord` a