Add phpcs, Travis, clean up editorconfig and eslint

extensions/markdown/.php_cs

@@ -0,0 +1,27 @@
+<?php
+
+$header = <<<EOF
+This file is part of Flarum.
+
+(c) Toby Zerner <toby.zerner@gmail.com>
+
+For the full copyright and license information, please view the LICENSE
+file that was distributed with this source code.
+EOF;
+
+Symfony\CS\Fixer\Contrib\HeaderCommentFixer::setHeader($header);
+
+$finder = Symfony\CS\Finder\DefaultFinder::create()
+    ->exclude('js')
+    ->exclude('less')
+    ->in(__DIR__);
+
+return Symfony\CS\Config\Config::create()
+    ->setUsingCache(true)
+    ->level(Symfony\CS\FixerInterface::PSR2_LEVEL)
+    ->fixers([
+        'short_array_syntax',
+        'header_comment',
+        '-psr0'
+    ])
+    ->finder($finder);