ScalaCheck 1.13!

[SethTisue]

this is already green locally when run against 2.12.1, except for a
few known failures that have already been seen elsewhere, and
a spray-json-shapeless failure that is probably unrelated and
that we can deal with separately later

cc @rickynils

this PR also:

• unfreezes argonaut (cc @seanparsons @xuwei-k)
• runs lift-json's test suite again (cc @Shadowfiend)
• adds cats-laws (cc @adelbertc @non)
• adds another monix subproject (cc @alexandru)

[rickynils]

Awesome!