Removed syntastic and replaced it with ale

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

sources_non_forked/ale/ale_linters/sass/sasslint.vim

@@ -0,0 +1,8 @@
+" Author: KabbAmine - https://github.com/KabbAmine
+
+call ale#linter#Define('sass', {
+\   'name': 'sasslint',
+\   'executable': 'sass-lint',
+\   'command': 'sass-lint -v -q -f compact %t',
+\   'callback': 'ale#handlers#css#HandleCSSLintFormat',
+\})

sources_non_forked/ale/ale_linters/sass/stylelint.vim

@@ -0,0 +1,22 @@
+" Author: diartyz <diartyz@gmail.com>
+
+call ale#Set('sass_stylelint_executable', 'stylelint')
+call ale#Set('sass_stylelint_use_global', 0)
+
+function! ale_linters#sass#stylelint#GetExecutable(buffer) abort
+    return ale#node#FindExecutable(a:buffer, 'sass_stylelint', [
+    \   'node_modules/.bin/stylelint',
+    \])
+endfunction
+
+function! ale_linters#sass#stylelint#GetCommand(buffer) abort
+    return ale_linters#sass#stylelint#GetExecutable(a:buffer)
+    \   . ' --stdin-filename %s'
+endfunction
+
+call ale#linter#Define('sass', {
+\   'name': 'stylelint',
+\   'executable_callback': 'ale_linters#sass#stylelint#GetExecutable',
+\   'command_callback': 'ale_linters#sass#stylelint#GetCommand',
+\   'callback': 'ale#handlers#css#HandleStyleLintFormat',
+\})