Cats 1.0.0 packaging

[kailuowang]

This is an issue consolidating all the packaging/publish related issues #1656, #1184, #472 and #592.
There are three separate decisions that are sort of related. It may make sense to decide on all of them all together. Here is the revised version of @BennyHill's summarization in this comment (I added more description for context)

1. Shall we continue publishing the current cats bundle which includes cats-laws and cats-free?
   The cats-laws includes a scalacheck dependency which surprises people.

Options are:
a) Keep as-is
b) Keep as-is but minus test libs
c) Rename as-is
d) Rename as-is but minus test libs
e) Remove

2. Shall we include alleycats into the cats repo as submodule? detailed discussion in Make Alleycats a submodule of Cats? #472

Options are:
a) Keep as-is, i.e. separate repo
b) move in as cats submodule. It will keep using a separate top alleycats namespace and will not be included in the cats bundle shall we decide to keep one. As a submodule, its releases will be part of cats release, but unlike cats-core, it is allowed to have binary breaking changes between patch versions for alley-cats, at least for now, since it's API hasn't reached the stable status yet.

3. Shall we publish cats-testkit? discussion in Publish cats-tests #1656

a) Create a new module called cats-testkit that includes the following utils from cats-tests: Helpers,
CatsSuite and CatsEquality
Note that these classes are not required for users to write cats style tests - cats-laws/discipline is the one that is required. cats-testkit will depend on cats-laws
b) keep as-is
c) simply publish cats-tests ( but not included in the cats bundle shall we have one. )

We've done extensive discussion around these for quite a while. So I propose we are ready to collect votes and see if we can reach consensus.

[kailuowang]

My vote
1, e
2.b changed to a, I don't see how alleycats is different from cats-mtl or cats-effects
3. a or b

[mpilquist]

1. e
2. a
3. b

[ghost]

My final vote
1, e
2. b
3. b (if we want common test-kits, move them to catalysts)

[djspiewak]

Only strong opinions are on 2 and 3. On 2, I strongly oppose moving alleycats into the cats repo. Polyrepo is significantly easier to manage here, and it ensures that the versioning is kept independent. Having things like alleycats, dogs, cats-mtl and cats-effect in repos that are separate from cats-core is a major win relative to the way that scalaz is setup, since scalaz's versioning is fundamentally tied together, meaning that changes which are non-breaking for core still have to increment the core breaking version, which in turn cascades through the entire ecosystem.

Regarding 3, option c seems fine, but I'm ok with any which publishes the test infrastructure.

[edmundnoble]

1. e
2. a
3. c please give me cats-tests.

[milessabin]

1. e
2. b
3. a or b

[kailuowang]

Results (if a vote for (a or b), I count both)

1. e (unanimous)
2. a 4, b 2
3. a 3, b 4, c 2

I think for 1.0.0-MF, we just do

1. e remove cats bundle,
2. a leave alleycats out of cats repo and
3. a release a test-kit, b got the most vote but I think a will make both a and c voters happy.