chapter 8 tests
8.14 Prop for List.sorted
The Scala Dreaded Underscore
8.14: Prop for List.takeWhile
8.14: Prop for List.takeWhile
tests for chapters 8,13
8.1,2 ScalaCheck Prop
14.1 STArray.fill
test for 14.1 STArray.fill
Merge branch 'master' of github.com:fpinscala-muc/fpinscala
exercises 6.2, 6.3, 6.4