Added DepotFile missing properties (#414)

* Added DepotFile missing properties

Author: alec-hs

steam/core/manifest.py

@@ -73,6 +73,22 @@ def linktarget(self):
         """
         return os.path.join(*self.linktarget_raw.split('\\'))
 
+    @property
+    def sha_content(self):
+        """File content SHA1 
+
+        :type: bytes
+        """
+        return self.file_mapping.sha_content
+
+    @property
+    def sha_filename(self):
+        """Filename SHA1 
+
+        :type: bytes
+        """
+        return self.file_mapping.sha_filename
+
     @property
     def size(self):
         """File size in bytes