Switched to 'await' and 'yield'
Updated documentation for yield category
Added 'Foldable' class re-export to "Pipes"
Updated documentation
Removed `map` and `mapM_`

These are both just trivial wrappers around `respond` and `lift`
Renamed 'filter' to 'yieldIf' and added 'replicate'
Added 'find'
Added 'findIndices'
Added 'replicateM'
Added `foldl'` and `foldM`
Added 'scanl'
Renamed `foldl'` to `foldl`
Changed how folds worked and added several new ones
Moved `tee` and `generalize` from `Pipes.Prelude` to `Pipes`
Renamed 'runEffect' to 'run'
Updated `discard` documentation
Updated documentation
Switched back 'run' to 'runEffect'
Updated documentation