Added functionality

lib
- Save
- DoAction
- ApplyDataset
- GetLayer(s)

main
- do actions from commandline

Improved test cases!

structs.go

@@ -0,0 +1,20 @@
+package ps
+
+// type layer interface {
+// 	Name() string
+// 	TextItem() []string
+// }
+
+type ArtLayer struct {
+	Name     string
+	TextItem string
+	Bounds   [2][2]string
+}
+
+// func (a *ArtLayer) Name() string {
+// 	return a.name
+// }
+
+// func (a *ArtLayer) TextItem() string {
+// 	return a.textItem
+// }