Removed syntastic and replaced it with ale

Read more here:
https://github.com/w0rp/ale

sources_non_forked/ale/ale_linters/haskell/ghc-mod.vim

@@ -0,0 +1,16 @@
+" Author: wizzup <wizzup@gmail.com>
+" Description: ghc-mod for Haskell files
+
+call ale#linter#Define('haskell', {
+\   'name': 'ghc-mod',
+\   'executable': 'ghc-mod',
+\   'command': 'ghc-mod --map-file %s=%t check %s',
+\   'callback': 'ale#handlers#haskell#HandleGHCFormat',
+\})
+
+call ale#linter#Define('haskell', {
+\   'name': 'stack-ghc-mod',
+\   'executable': 'stack',
+\   'command': 'stack exec ghc-mod -- --map-file %s=%t check %s',
+\   'callback': 'ale#handlers#haskell#HandleGHCFormat',
+\})