feat: Turtle.get_Duration default ( Fixes #270 )

Author: StartAutomating

Types/Turtle/get_Duration.ps1

@@ -3,6 +3,10 @@
     Gets the duration
 .DESCRIPTION
     Gets the default duration of animations and morphs.
+
+    By default, 4.2 seconds.
 #>
-if ($this.'.Duration') { return $this.'.Duration'}
-return
+if ($null -eq $this.'.Duration') { 
+    $this | Add-Member NoteProperty '.Duration' ([timespan]::FromSeconds(4.2)) -Force
+}
+return $this.'.Duration'