intermediate commit

* Implement move artifact action
* Fix widget update memory leak
  * update the highlights not during on each frame
  * do not update the unchanged label of a button
* Allow to exit the game by pressing 'q'
* Implement some cards from the magic set
* Improve permanent formatting
* Some tweaks to UnitAI code

1 files changed, 4 insertions, 2 deletions

diff --git a/go/ui/button.go b/go/ui/button.go
index 50f78a3d..e882d39c 100644
--- a/go/ui/button.go
+++ b/go/ui/button.go
@@ -46,6 +46,8 @@ func (b *SimpleButton) Click(x, y int) {
 }
 
 func (b *SimpleButton) UpdateLabel(label string) {
-	b.label = label
-	b.ForceRedraw()
+	if b.label != label {
+		b.label = label
+		b.ForceRedraw()
+	}
 }