Removed syntastic and replaced it with ale

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

sources_non_forked/ale/autoload/ale/handlers/redpen.vim

@@ -0,0 +1,56 @@
+" Author: rhysd https://rhysd.github.io
+" Description: Redpen, a proofreading tool (http://redpen.cc)
+
+function! ale#handlers#redpen#HandleRedpenOutput(buffer, lines) abort
+    " Only one file was passed to redpen. So response array has only one
+    " element.
+    let l:res = json_decode(join(a:lines))[0]
+    let l:output = []
+    for l:err in l:res.errors
+        let l:item = {
+        \   'text': l:err.message,
+        \   'type': 'W',
+        \   'code': l:err.validator,
+        \}
+        if has_key(l:err, 'startPosition')
+            let l:item.lnum = l:err.startPosition.lineNum
+            let l:item.col = l:err.startPosition.offset + 1
+            if has_key(l:err, 'endPosition')
+                let l:item.end_lnum = l:err.endPosition.lineNum
+                let l:item.end_col = l:err.endPosition.offset
+            endif
+        else
+            " Fallback to a whole sentence region when a region is not
+            " specified by the error.
+            let l:item.lnum = l:err.lineNum
+            let l:item.col = l:err.sentenceStartColumnNum + 1
+        endif
+
+        " Adjust column number for multibyte string
+        let l:line = getline(l:item.lnum)
+        if l:line is# ''
+            let l:line = l:err.sentence
+        endif
+        let l:line = split(l:line, '\zs')
+
+        if l:item.col >= 2
+            let l:col = 0
+            for l:strlen in map(l:line[0:(l:item.col - 2)], 'strlen(v:val)')
+                let l:col = l:col + l:strlen
+            endfor
+            let l:item.col = l:col + 1
+        endif
+
+        if has_key(l:item, 'end_col')
+            let l:col = 0
+            for l:strlen in map(l:line[0:(l:item.end_col - 1)], 'strlen(v:val)')
+                let l:col = l:col + l:strlen
+            endfor
+            let l:item.end_col = l:col
+        endif
+
+        call add(l:output, l:item)
+    endfor
+    return l:output
+endfunction
+