Removed syntastic and replaced it with ale

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

sources_non_forked/ale/ale_linters/yaml/yamllint.vim

@@ -0,0 +1,48 @@
+" Author: KabbAmine <amine.kabb@gmail.com>
+
+let g:ale_yaml_yamllint_executable =
+\   get(g:, 'ale_yaml_yamllint_executable', 'yamllint')
+
+let g:ale_yaml_yamllint_options =
+\   get(g:, 'ale_yaml_yamllint_options', '')
+
+function! ale_linters#yaml#yamllint#GetExecutable(buffer) abort
+    return ale#Var(a:buffer, 'yaml_yamllint_executable')
+endfunction
+
+function! ale_linters#yaml#yamllint#GetCommand(buffer) abort
+    return ale_linters#yaml#yamllint#GetExecutable(a:buffer)
+    \   . ' ' . ale#Var(a:buffer, 'yaml_yamllint_options')
+    \   . ' -f parsable %t'
+endfunction
+
+function! ale_linters#yaml#yamllint#Handle(buffer, lines) abort
+    " Matches patterns line the following:
+    " something.yaml:1:1: [warning] missing document start "---" (document-start)
+    " something.yml:2:1: [error] syntax error: expected the node content, but found '<stream end>'
+    let l:pattern = '^.*:\(\d\+\):\(\d\+\): \[\(error\|warning\)\] \(.\+\)$'
+    let l:output = []
+
+    for l:match in ale#util#GetMatches(a:lines, l:pattern)
+        let l:line = l:match[1] + 0
+        let l:col = l:match[2] + 0
+        let l:type = l:match[3]
+        let l:text = l:match[4]
+
+        call add(l:output, {
+        \   'lnum': l:line,
+        \   'col': l:col,
+        \   'text': l:text,
+        \   'type': l:type is# 'error' ? 'E' : 'W',
+        \})
+    endfor
+
+    return l:output
+endfunction
+
+call ale#linter#Define('yaml', {
+\   'name': 'yamllint',
+\   'executable_callback': 'ale_linters#yaml#yamllint#GetExecutable',
+\   'command_callback': 'ale_linters#yaml#yamllint#GetCommand',
+\   'callback': 'ale_linters#yaml#yamllint#Handle',
+\})