Removed syntastic and replaced it with ale

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

sources_non_forked/ale/ale_linters/php/phpmd.vim

@@ -0,0 +1,45 @@
+" Author: medains <https://github.com/medains>, David Sierra <https://github.com/davidsierradz>
+" Description: phpmd for PHP files
+
+let g:ale_php_phpmd_executable = get(g:, 'ale_php_phpmd_executable', 'phpmd')
+
+" Set to change the ruleset
+let g:ale_php_phpmd_ruleset = get(g:, 'ale_php_phpmd_ruleset', 'cleancode,codesize,controversial,design,naming,unusedcode')
+
+function! ale_linters#php#phpmd#GetExecutable(buffer) abort
+    return ale#Var(a:buffer, 'php_phpmd_executable')
+endfunction
+
+function! ale_linters#php#phpmd#GetCommand(buffer) abort
+    let l:executable = ale_linters#php#phpmd#GetExecutable(a:buffer)
+
+    return ale#Escape(l:executable)
+    \   . ' %s text '
+    \   . ale#Var(a:buffer, 'php_phpmd_ruleset')
+    \   . ' --ignore-violations-on-exit %t'
+endfunction
+
+function! ale_linters#php#phpmd#Handle(buffer, lines) abort
+    " Matches against lines like the following:
+    "
+    " /path/to/some-filename.php:18 message
+    let l:pattern = '^.*:\(\d\+\)\s\+\(.\+\)$'
+    let l:output = []
+
+    for l:match in ale#util#GetMatches(a:lines, l:pattern)
+        call add(l:output, {
+        \   'lnum': l:match[1] + 0,
+        \   'text': l:match[2],
+        \   'type': 'W',
+        \})
+    endfor
+
+    return l:output
+endfunction
+
+call ale#linter#Define('php', {
+\   'name': 'phpmd',
+\   'executable_callback': 'ale_linters#php#phpmd#GetExecutable',
+\   'command_callback': 'ale_linters#php#phpmd#GetCommand',
+\   'callback': 'ale_linters#php#phpmd#Handle',
+\})