New module: XMonad.Prelude

This is a convenience module in order to have less import noise.  It
re-exports the following:

  a) Commonly used modules in full (Data.Foldable, Data.Applicative, and
     so on); though only those that play nicely with each other, so that
     XMonad.Prelude can be imported unqualified without any problems.
     This prevents things like `Prelude.(.)` and `Control.Category.(.)`
     fighting with each other.

  b) Helper functions that don't necessarily fit in any other module;
     e.g., the often used abbreviation `fi = fromIntegral`.

tests/XPrompt.hs

@@ -9,6 +9,7 @@ module XPrompt where
 
 import Test.QuickCheck
 
+import XMonad.Prelude (chunksOf)
 import XMonad.Prompt
 import qualified XMonad.Prompt.Shell as S
 
@@ -20,7 +21,7 @@ prop_split (str :: String) =
 -- of the string.
 prop_spliInSubListsAt (x :: Int) (str :: String) =
     x < length str ==> result == take x str
-    where result = case splitInSubListsAt x str of
+    where result = case chunksOf x str of
                      [] -> []
                      x -> head x