Enforce GHC >= 7.10 and fix Stack warnings

src/PostgREST/Parsers.hs

@@ -4,10 +4,6 @@ module PostgREST.Parsers
 where
 
 import           Control.Applicative hiding ((<$>))
---lines needed for ghc 7.8
-import           Data.Functor ((<$>))
-import           Data.Traversable (traverse)
-
 import           Control.Monad                 (join)
 import           Data.List                     (delete, find)
 import           Data.Maybe