Registration refactoring step 1: Added abstract type Registration to TestRegistration trait that is the return type of the test function passed to registerTest and registerIgnoredTest, make a new ClassicTests trait that set the abstract Registration type to Unit (which is the current return type of test functions), and mixed it in to style classes.
Registration refactoring step 2: Renamed current XXXLike to XXXRegistration, and create new XXXLike that extends XXXRegistration and mixed in ClassicTests, and finally removed with ClassicTests in the style class.
Completed registration refactoring in fixture package.
Added AsyncFixtures.
Merge branch 'registration' of https://github.com/cheeseng/scalatest