Removed syntastic and replaced it with ale

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

sources_non_forked/ale/ale_linters/javascript/eslint.vim

@@ -0,0 +1,10 @@
+" Author: w0rp <devw0rp@gmail.com>
+" Description: eslint for JavaScript files
+
+call ale#linter#Define('javascript', {
+\   'name': 'eslint',
+\   'output_stream': 'both',
+\   'executable_callback': 'ale#handlers#eslint#GetExecutable',
+\   'command_callback': 'ale#handlers#eslint#GetCommand',
+\   'callback': 'ale#handlers#eslint#Handle',
+\})