Removed syntastic and replaced it with ale

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

sources_non_forked/ale/ale_linters/tex/chktex.vim

@@ -0,0 +1,54 @@
+" Author: Andrew Balmos - <andrew@balmos.org>
+" Description: chktex for LaTeX files
+
+let g:ale_tex_chktex_executable =
+\   get(g:, 'ale_tex_chktex_executable', 'chktex')
+
+let g:ale_tex_chktex_options =
+\   get(g:, 'ale_tex_chktex_options', '-I')
+
+function! ale_linters#tex#chktex#GetCommand(buffer) abort
+    " Check for optional .chktexrc
+    let l:chktex_config = ale#path#FindNearestFile(
+    \   a:buffer,
+    \   '.chktexrc')
+
+    let l:command = ale#Var(a:buffer, 'tex_chktex_executable')
+    " Avoid bug when used without -p (last warning has gibberish for a filename)
+    let l:command .= ' -v0 -p stdin -q'
+
+    if !empty(l:chktex_config)
+        let l:command .= ' -l ' . ale#Escape(l:chktex_config)
+    endif
+
+    let l:command .= ' ' . ale#Var(a:buffer, 'tex_chktex_options')
+
+    return l:command
+endfunction
+
+function! ale_linters#tex#chktex#Handle(buffer, lines) abort
+    " Mattes lines like:
+    "
+    " stdin:499:2:24:Delete this space to maintain correct pagereferences.
+    " stdin:507:81:3:You should enclose the previous parenthesis with `{}'.
+    let l:pattern = '^stdin:\(\d\+\):\(\d\+\):\(\d\+\):\(.\+\)$'
+    let l:output = []
+
+    for l:match in ale#util#GetMatches(a:lines, l:pattern)
+        call add(l:output, {
+        \   'lnum': l:match[1] + 0,
+        \   'col': l:match[2] + 0,
+        \   'text': l:match[4] . ' (' . (l:match[3]+0) . ')',
+        \   'type': 'W',
+        \})
+    endfor
+
+    return l:output
+endfunction
+
+call ale#linter#Define('tex', {
+\   'name': 'chktex',
+\   'executable': 'chktex',
+\   'command_callback': 'ale_linters#tex#chktex#GetCommand',
+\   'callback': 'ale_linters#tex#chktex#Handle'
+\})