feat: Turtle.Save() ( Fixes #105 )

Using splatting to avoid trying to save a blank property

Author: James Brundage

Types/Turtle/Save.ps1

@@ -7,11 +7,17 @@
     Save-Turtle
 #>
 param(
+[Parameter(Mandatory)]
 [string]
 $FilePath,
 
 [string]
 $Property
 )
 
-return $this | Save-Turtle $FilePath -Property $Property
+$saveSplat = [Ordered]@{FilePath = $FilePath}
+if ($Property) {
+    $saveSplat.Property = $property
+}
+
+return $this | Save-Turtle @saveSplat