Issue 46: Add laws verification for Read

[barambani]

This is a first attempt at #46 . A couple of notes. The most important, I couldn't find a way to make our Read flatMap or the instance tailRecM stack safe so for now I'm checking the stackUnsafeMonad laws. Also the Eq definition I used for Read is based on a single sample. I might add some other attempts.

[barambani]

One more thing, I didn't define the Invariant functor as our Contravariant doesn't act on the same type parameter as the Covariant. We will have to decide if and how we want the invariant to be.

[codecov-io]

Codecov Report

Merging #198 into master will increase coverage by 0.08%.
The diff coverage is 62.5%.

@@            Coverage Diff             @@
##           master     #198      +/-   ##
==========================================
+ Coverage   59.71%   59.79%   +0.08%     
==========================================
  Files          37       38       +1     
  Lines        1276     1291      +15     
  Branches        7        8       +1     
==========================================
+ Hits          762      772      +10     
- Misses        514      519       +5

Impacted Files	Coverage Δ
core/src/main/scala/laserdisc/protocol/Read.scala	76.66% <100%> (+1.03%)	⬆️
.../main/scala/laserdisc/protocol/ReadInstances.scala	57.14% <57.14%> (ø)

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[sirocchj]

Love it