Make value getters/setters more consistent

See #6

numberinput.go

@@ -15,8 +15,8 @@ type NumberInput struct {
 	increment *Button
 	decrement *Button
 	on struct {
-		enter event.FuncBroadcaster
-		edit  event.FuncBroadcaster
+		enter       event.FuncBroadcaster
+		valueChange event.FuncBroadcaster
 	}
 }
 
@@ -44,37 +44,38 @@ func NewNumberInput (value float64) *NumberInput {
 	box.OnScroll(box.handleScroll)
 	box.OnKeyDown(box.handleKeyDown)
 	box.input.OnEnter(box.handleEnter)
-	box.input.OnEdit(box.on.edit.Broadcast)
+	box.input.OnValueChange(box.on.valueChange.Broadcast)
 	box.increment.OnClick(func () { box.shift(1)  })
 	box.decrement.OnClick(func () { box.shift(-1) })
 	return box
 }
 
-// SetValue sets the value of the input.
-func (this *NumberInput) SetValue (value float64) {
-	this.input.SetText(strconv.FormatFloat(value, 'g', -1, 64))
-}
-
 // Value returns the value of the input.
 func (this *NumberInput) Value () float64 {
 	value, _ := strconv.ParseFloat(this.input.Text(), 64)
 	return value
 }
 
+// SetValue sets the value of the input.
+func (this *NumberInput) SetValue (value float64) {
+	this.input.SetText(strconv.FormatFloat(value, 'g', -1, 64))
+}
+
+// OnValueChange specifies a function to be called when the user edits the input
+// value.
+func (this *NumberInput) OnValueChange (callback func ()) event.Cookie {
+	return this.on.valueChange.Connect(callback)
+}
+
 // OnEnter specifies a function to be called when the user presses enter within
 // the text input.
 func (this *NumberInput) OnEnter (callback func ()) event.Cookie {
 	return this.on.enter.Connect(callback)
 }
 
-// OnEdit specifies a function to be called when the user edits the input value.
-func (this *NumberInput) OnEdit (callback func ()) event.Cookie {
-	return this.on.edit.Connect(callback)
-}
-
 func (this *NumberInput) shift (by int) {
 	this.SetValue(this.Value() + float64(by))
-	this.on.edit.Broadcast()
+	this.on.valueChange.Broadcast()
 }
 
 func (this *NumberInput) handleKeyDown (key input.Key, numpad bool) {