Removed syntastic and replaced it with ale

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

sources_non_forked/ale/ale_linters/swift/swiftlint.vim

@@ -0,0 +1,51 @@
+" Author: David Mohundro <david@mohundro.com>
+" Description: swiftlint for swift files
+
+
+function! ale_linters#swift#swiftlint#Handle(buffer, lines) abort
+    let l:pattern = '\v^([a-zA-Z]?:?[^:]+):(\d+):(\d+)?:? ([^:]+): (.+)$'
+    let l:output = []
+
+    for l:match in ale#util#GetMatches(a:lines, l:pattern)
+        let l:item = {
+        \   'lnum': str2nr(l:match[2]),
+        \   'type': l:match[4] is# 'error' ? 'E' : 'W',
+        \   'text': l:match[5],
+        \}
+
+        if l:match[4] is# 'error'
+            let l:item.type = 'E'
+        elseif l:match[4] is# 'note'
+            let l:item.type = 'I'
+        endif
+
+        if !empty(l:match[3])
+            let l:item.col = str2nr(l:match[3])
+        endif
+
+        " If the filename is something like <stdin>, <nofile> or -, then
+        " this is an error for the file we checked.
+        if l:match[1] isnot# '-' && l:match[1][0] isnot# '<'
+            let l:item['filename'] = l:match[1]
+        endif
+
+        " Parse the code if it's there.
+        let l:code_match = matchlist(l:item.text, '\v^(.+) \(([^ (]+)\)$')
+
+        if !empty(l:code_match)
+            let l:item.text = l:code_match[1]
+            let l:item.code = l:code_match[2]
+        endif
+
+        call add(l:output, l:item)
+    endfor
+
+    return l:output
+endfunction
+
+call ale#linter#Define('swift', {
+\   'name': 'swiftlint',
+\   'executable': 'swiftlint',
+\   'command': 'swiftlint lint --use-stdin',
+\   'callback': 'ale_linters#swift#swiftlint#Handle',
+\})