Implement Serde

[Deedasmi]

Apologies for the previous PR, I got over-eager and apparently lost my mind. This just simply uses serde's derive functions which should be a lot lower of a maintenance burden at the cost of some more compile time.

Closes #7.

[JelteF]

Those changes look fine, but I'm surprised the default itself is part of the serialisation. Is that really useful? I would think it should serialise as a regular map.

Also, can you make some tests that start from a json string? That way it's much clearer what the serialization results in.

[Deedasmi]

That's actually what I did in #8, and it worked fine. But had an issue where you could serialize anything that would go into DefaultHashMap, but could only deserialize data that implemented Default back into DefaultHashMap.

Additionally, I came across a different situation where my default value was user-input based. Instead of having to save both when you need both, just decided to serialize it with the map. Can always drop it if you don't need it.

And yeah, I'll add some more test cases soon.

[codecov-io]

Codecov Report

Merging #9 into master will decrease coverage by 0.13%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master       #9      +/-   ##
==========================================
- Coverage   95.96%   95.83%   -0.14%     
==========================================
  Files           1        1              
  Lines         124      120       -4     
==========================================
- Hits          119      115       -4     
  Misses          5        5

Impacted Files	Coverage Δ
src/lib.rs	95.83% <ø> (-0.14%)	⬇️

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[JelteF]

Fixed the merge conflict and squashed the commits. This is now on master.

[JelteF]

Thanks for your work on this.

[JelteF]

I just released this in 0.5.0