Removed syntastic and replaced it with ale

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

sources_non_forked/ale/ale_linters/php/hack.vim

@@ -0,0 +1,28 @@
+" Author: Zefei Xuan <https://github.com/zefei>
+" Description: Hack type checking (http://hacklang.org/)
+
+function! ale_linters#php#hack#Handle(buffer, lines) abort
+    let l:pattern = '^\(.*\):\(\d\+\):\(\d\+\),\(\d\+\): \(.\+])\)$'
+    let l:output = []
+
+    for l:match in ale#util#GetMatches(a:lines, l:pattern)
+        if a:buffer != bufnr(l:match[1])
+            continue
+        endif
+
+        call add(l:output, {
+        \   'lnum': l:match[2] + 0,
+        \   'col': l:match[3] + 0,
+        \   'text': l:match[5],
+        \})
+    endfor
+
+    return l:output
+endfunction
+
+call ale#linter#Define('php', {
+\   'name': 'hack',
+\   'executable': 'hh_client',
+\   'command': 'hh_client --retries 0 --retry-if-init false',
+\   'callback': 'ale_linters#php#hack#Handle',
+\})