feat: Turtle default display ( Fixes #24 )

Author: James Brundage

Turtle.types.ps1xml

@@ -24,6 +24,25 @@ $x = $Distance * [math]::round([math]::cos($this.Heading * [Math]::PI / 180),15)
 $y = $Distance * [math]::round([math]::sin($this.Heading * [Math]::PI / 180),15)
 $this.Position = $x, $y
 $this.Steps += "l $x $y"
+return $this
+                    </Script>
+      </ScriptMethod>
+      <ScriptMethod>
+        <Name>HilbertCurve</Name>
+        <Script>
+                        param(
+    [double]$Size = 10,
+    [int]$Order = 5,
+    [double]$Angle = 90
+)        
+$this.L('A',  @{
+    A = '+BF-AFA-FB+'
+    B = '-AF+BFB+FA-'
+}, $Order, @{
+    'F'     = { $this.Forward($Size) }
+    '\+'    = { $this.Rotate($Angle) }
+    '\-'    = { $this.Rotate($Angle * -1) }
+})
 return $this
                     </Script>
       </ScriptMethod>