Bump resolvers to lts-9.0 (#732)

* Bump resolvers to lts-9.0

* Import HLint3 instead of HLint2

.travis.yml

 # Test against different stack LTS versions.
 env:
- - DISPLAY=true   RESOLVER=lts-8.23 # GHC 8.0.2
+ - DISPLAY=true   RESOLVER=lts-9.0 # GHC 8.0.2
 
 # Choose a lightweight base image; we provide our own build tools.
 language: python

ihaskell-display/ihaskell-aeson/stack.yaml

 flags: {}
 packages:
 - '.'
-resolver: lts-8.23
+resolver: lts-9.0

ihaskell-display/ihaskell-blaze/stack.yaml

 flags: {}
 packages:
 - '.'
-resolver: lts-8.23
+resolver: lts-9.0

ihaskell-display/ihaskell-charts/stack.yaml

 flags: {}
 packages:
 - '.'
-resolver: lts-8.23
+resolver: lts-9.0

ihaskell-display/ihaskell-diagrams/stack.yaml

 flags: {}
 packages:
 - '.'
-resolver: lts-8.23
+resolver: lts-9.0

ihaskell-display/ihaskell-gnuplot/stack.yaml

 flags: {}
 packages:
 - '.'
-resolver: lts-8.23
+resolver: lts-9.0
 extra-deps: []

ihaskell-display/ihaskell-hatex/stack.yaml

 flags: {}
 packages:
 - '.'
-resolver: lts-8.23
+resolver: lts-9.0

ihaskell-display/ihaskell-juicypixels/stack.yaml

 flags: {}
 packages:
 - '.'
-resolver: lts-8.23
+resolver: lts-9.0

ihaskell-display/ihaskell-magic/stack.yaml

 flags: {}
 packages:
 - '.'
-resolver: lts-8.23
+resolver: lts-9.0

ihaskell-display/ihaskell-plot/stack.yaml

 flags: {}
 packages:
 - '.'
-resolver: lts-8.23
+resolver: lts-9.0

ihaskell-display/ihaskell-rlangqq/stack.yaml

 flags: {}
 packages:
 - '.'
-resolver: lts-8.23
+resolver: lts-9.0

ihaskell-display/ihaskell-static-canvas/stack.yaml

 flags: {}
 packages:
 - '.'
-resolver: lts-8.23
+resolver: lts-9.0

ihaskell-display/ihaskell-widgets/stack.yaml

 flags: {}
 packages:
 - '.'
-resolver: lts-8.23
+resolver: lts-9.0

src/IHaskell/Eval/Lint.hs

@@ -25,7 +25,7 @@ import           Language.Haskell.Exts hiding (Module)
 import           Language.Haskell.Exts.SrcLoc
 
 import           Language.Haskell.HLint as HLint
-import           Language.Haskell.HLint2
+import           Language.Haskell.HLint3
 
 import           IHaskell.Types
 import           IHaskell.Display

stack.yaml

@@ -14,7 +14,7 @@ packages:
     - ./ihaskell-display/ihaskell-plot
     - ./ihaskell-display/ihaskell-static-canvas
     - ./ihaskell-display/ihaskell-widgets
-resolver: lts-8.23
+resolver: lts-9.0
 extra-deps: []
 flags:
   ihaskell: