make buttons transperent and add tooltip

src/.import/pause.png-2588384f69d078ed3af39e5e39672e7d.md5

@@ -1,3 +1,3 @@
-source_md5="ea70ad65cae93d474483e7709e543dac"
-dest_md5="59c8e93bedf75c1f3aa313f10b030468"
+source_md5="e76f3139946352482d37d01b84f5211c"
+dest_md5="b993a484485af4ae34dc9d333a52a9d1"
 

src/.import/speed.png-75f5ca870dd580ad6bde90f6052ac60c.md5

@@ -1,3 +1,3 @@
-source_md5="d81b98260931c2758f0a53edaa052c2e"
-dest_md5="ea3bcd09037e5a0180b92cb09eee9e82"
+source_md5="857cae8bc4bdd558d18df71e9ea061fd"
+dest_md5="0a6a9af1b0eafef2b97503c75a6a597d"
 

src/UI/GUI.tscn

@@ -24,18 +24,22 @@ __meta__ = {
 margin_left = 2.0
 margin_right = 24.0
 margin_bottom = 20.0
+hint_tooltip = "Pause"
 size_flags_horizontal = 0
 size_flags_vertical = 0
 toggle_mode = true
 icon = ExtResource( 1 )
+flat = true
 
 [node name="speed" type="Button" parent="HBoxContainer"]
 margin_left = 28.0
 margin_right = 55.0
 margin_bottom = 20.0
+hint_tooltip = "Double speed"
 size_flags_horizontal = 0
 size_flags_vertical = 0
 toggle_mode = true
 icon = ExtResource( 2 )
+flat = true
 [connection signal="toggled" from="HBoxContainer/pause" to="." method="_on_pause_toggled"]
 [connection signal="toggled" from="HBoxContainer/speed" to="." method="_on_speed_toggled"]