PSD: improved option support

Added support for the following options:
- `ImageTransformation`: uses EXIF data (same behaviour of Photoshop and GIMP)
- `Description`: uses EXIF data
- `ImageFormat` 

Closes #17

autotests/read/psd/orientation1.psd.json

@@ -0,0 +1,11 @@
+[
+    {
+        "fileName" : "orientation_all.png",
+        "metadata" : [
+            {
+                "key" : "Software" ,
+                "value" : "LIFE Pro 2.18.5 (Windows)"
+            }
+        ]
+    }
+]