Please support Serialize for generated Diff structs #75
Description
We're using this crate at work to generate diffs between complicated structs.
Recently it became necessary to serialize differences out to file, so I added quick and dirty Serialize support by putting #[derive(Serialize)] in a small number of places. (see here)
The main problem with this approach (beyond being a dirty hack) is that the entire Diff structure is serialized rather than just the branches/leaves with changes in them.
I'm not good enough with macros to attempt to change that.
Would you please consider making Diff structs serializable in a way that leaves out unchanged parts? It'd be extremely helpful. Thanks!