Wrap game resource info from the server

Also add function to get the diff archive (for faster updating)

Download function soon, although I can't make sure that the download function will work properly (like pause, resume download etc.)

worthless/classes/installer/diff.py

@@ -0,0 +1,21 @@
+from worthless.classes.installer.voicepack import Voicepack
+
+
+class Diff:
+    def __init__(self, name, version, path, size, md5, is_recommended_update, voice_packs, raw):
+        self.name = name
+        self.version = version
+        self.path = path
+        self.size = size
+        self.md5 = md5
+        self.is_recommended_update = is_recommended_update
+        self.voice_packs = voice_packs
+        self.raw = raw
+
+    @staticmethod
+    def from_dict(data):
+        voice_packs = []
+        for v in data['voice_packs']:
+            voice_packs.append(Voicepack.from_dict(v))
+        return Diff(data["name"], data["version"], data["path"], data["size"], data["md5"],
+                    data["is_recommended_update"], voice_packs, data)