Don't serialize ScriptGuid, UniqueId, and HistoryId (#327)

Closes #314 and resolves #324 for now.

I've decided that `LuaSourceContainer.ScriptGuid`, `Instance.UniqueId`,
and `Instance.HistoryId` shouldn't serialize for the time being. All
they do is make diff noise and they aren't especially useful for Rojo or
Lune users at this time.

In the process, I discovered that `rbx_reflector` actually wasn't
catching `UniqueId` properties so I've corrected that. I'll add it to my
list of things to check in new data type implementations going forward.

patches/instance.yml

@@ -1,5 +1,16 @@
 Change:
   Instance:
+    # UniqueId properties might be random everytime Studio saves a place file
+    # and don't have a use right now outside of packages, which Rojo doesn't
+    # account for anyway. They generate diff noise, so we shouldn't serialize
+    # them until we have to.
+    UniqueId:
+      Serialization:
+        Type: DoesNotSerialize
+    HistoryId:
+      Serialization:
+        Type: DoesNotSerialize
+
     archivable:
       AliasFor: Archivable
     Archivable:

patches/lua-source-container.yml

@@ -0,0 +1,7 @@
+Change:
+  LuaSourceContainer:
+    # ScriptGuid is randomly generated everytime a script is saved from Studio
+    # and it makes no sense for us to write it ourselves at this moment.
+    ScriptGuid:
+      Serialization:
+        Type: DoesNotSerialize