add Lens for Map.WithDefault

For when you don't need a PLens.
standalone Set membership lens

Similar to SetLensFamily.contains, but doesn't require input Lens.
Change Scalacheck URL to use Scaladoc syntax so generated HTML is valid
update scala-parser-combinators and scala-xml version
add kleisliProfunctor and kleisliCompose
Kleisli test
add cokleisliEndoInstance, kleisliEndoSemigroup, cokleisliEndoSemigroup
add EndomorphicTest
Implement traverseU_
Merge pull request #547 from refried/patch-10

add Lens for Map.WithDefault
Merge pull request #548

standalone Set membership lens
Merge pull request #556 from adelbertc/fix-scalacheck-url

Change Scalacheck URL to use Scaladoc syntax so generated HTML is valid
Merge pull request #558 from bmjames/traverseU_

Unapply version of traverse_
s/7.0.3/7.0.4
Prevent an unnecessary allocation on Either.getOrElse
Merge pull request #559 from japgolly/either

Prevent an unnecessary allocation on Either.getOrElse
relax constraint
prevent an unnecessary allocation Either.leftMap
make \&/ covariant