Added a from(Option, orError) method to Or's companion.
Added EitherSugar, TrySugar, and OptionSugar, which add toOr methods to those types.
Merge branch '2.2.x' of https://github.com/scalatest/scalatest
Added some extra implicit classes in TrySugar and EitherSugar to deal with the retracted Nothing feature.
Merge branch '2.2.x' of https://github.com/scalatest/scalatest
Refactored how tests are run in Engine.