more bits of docs

Originally filed as #249, squashed and tuned by @larsrh.
run gen-type-class
tuned
Upgrade IO#catchLeft and IO#catchSomeLeft to scalaz.\/
Merge pull request #252 from bmjames/scalaz-seven

Upgrade IO#catchLeft and IO#catchSomeLeft to GlorifiedTuple
Specialize foldLeft for NonEmptyList; foldLeft/foldLeft1 for Tree.
Merge pull request #253 from S11001001/topic/nel-fold-left

Specialize foldLeft for NonEmptyList; foldLeft/foldLeft1 for Tree.
Order[A @@ Dual] is flipped Order[A], if scalaz.Dual._ is imported.
Fix doc example of using Tags.Dual.
Merge pull request #254 from S11001001/topic/dual-order+doc

flipped Order[A @@ Dual]