Changed serialization breaks things

In 0.32.3 serialization was changed, as per the changelog:
> Statically sized matrices are now serialized as tuples to match how serde serialized plain arrays.

This has the unfortunate effect of making it impossible to deserialize data serialized by previous versions of Nalgebra using version 0.32.3 (and vice versa). In my case, all the assets of my game are serialized using serde+bincode. Since all asset types contain Nalgebra types, the asset files can no longer be deserialized after upgrading Nalgebra.

The solution was pretty convoluted and brittle. I had to create a converter program that:

- Reads (deserializes) assets using Nalgebra 0.32.2
- Re-implements all the asset types verbatim, but using Nalgebra 0.32.3 types
- `mem::transmute`s all the assets from the old types to the new
- Writes (serializes) new assets back to disk

Maybe there is a smarter way, but I could not come up with anything. Anyway, to avoid similar problems in the future, I would suggest

- Only breaking serialization/deserialization backward compatibility when absolutely necessary
- Flagging the changes as breaking, preferably using SemVer