Fix #11: Right click support.

When clicked, Button() and Input() return the respective mouse button
constant ('l', 'r', 'm') instead of just true.
When activated by keyboard, Button() and Input() return 'return'.
Otherwise Button() and Input() return false.

button.lua

@@ -72,6 +72,6 @@ return function(w)
 	core.registerDraw(id, w.draw or core.style.Button,
 		w.text, pos[1],pos[2], size[1],size[2])
 
-	return mouse.releasedOn(id) or (keyboard.key == 'return' and keyboard.hasFocus(id))
+	return mouse.releasedOn(id) or keyboard.pressedOn(id, 'return')
 end
 

input.lua

@@ -74,5 +74,5 @@ return function(w)
 	core.registerDraw(id, w.draw or core.style.Input,
 		w.info.text, w.info.cursor, pos[1],pos[2], size[1],size[2])
 
-	return mouse.releasedOn(id) or (keyboard.key == 'return' and keyboard.hasFocus(id))
+	return mouse.releasedOn(id) or keyboard.pressedOn(id, 'return')
 end

keyboard.lua

@@ -70,6 +70,10 @@ local function makeCyclable(id)
 	lastwidget = id
 end
 
+local function pressedOn(id, k)
+	return (k or 'return') == key and hasFocus(id) and k
+end
+
 local function beginFrame()
 	-- for future use?
 end
@@ -88,6 +92,7 @@ return setmetatable({
 	clearFocus    = clearFocus,
 	hasFocus      = hasFocus,
 	makeCyclable  = makeCyclable,
+	pressedOn     = pressedOn,
 
 	disable       = disable,
 	enable        = clearFocus,

mouse.lua

@@ -27,7 +27,7 @@ THE SOFTWARE.
 local _M -- holds the module. needed to make widgetHit overridable
 
 local x,y = 0,0
-local down = false
+local down, downLast = false, false
 local hot, active = nil, nil
 local NO_WIDGET = {}
 local function _NOP_() end
@@ -55,13 +55,17 @@ local function updateWidget(id, pos, size, hit)
 end
 
 local function releasedOn(id)
-	return not down and isHot(id) and isActive(id)
+	return not down and isHot(id) and isActive(id) and downLast
 end
 
 local function beginFrame()
 	hot = nil
 	x,y = love.mouse.getPosition()
-	down = love.mouse.isDown('l')
+	downLast = down
+	down = false
+	for _,btn in ipairs{'l', 'm', 'r'} do
+		down = down or (love.mouse.isDown(btn) and btn)
+	end
 end
 
 local function endFrame()