Drop support for GHC-7.8.4

Data/GraphQL/Parser.hs

@@ -1,14 +1,9 @@
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE OverloadedStrings #-}
 -- | This module defines a parser for @GraphQL@ request documents.
 module Data.GraphQL.Parser where
 
 import Prelude hiding (takeWhile)
 
-#if !MIN_VERSION_base(4,8,0)
-import Control.Applicative ((<$>), (<*>), (*>), (<*), (<$), pure)
-import Data.Monoid (Monoid, mempty)
-#endif
 import Control.Applicative ((<|>), empty, many, optional)
 import Control.Monad (when)
 import Data.Char (isDigit, isSpace)