Merge pull request #4 from maxsnew/master

Update for Elm 0.12.1
Added documentation for loop, changed hiddenState to match loop's type signature
Fixed average, added branch and extendDown
Added extendUp
Added before, stack. Fixed formatting on andThen, fixed extendUp
Added reduceWith, reworded some comments
Updated documentation, version number
Changed names as per Evan's suggestions
Changed functions to (<<<) and (>>>), updated version number.
Merge pull request #5 from stepvhen/master

Expansion of library
Update for 0.13 import syntax
Improve comments drastically, change merge type
improve docs a bit
cosmetic: be more consistent with indentation
Fix for Elm 0.13