Add php-cs-fixer.

Signed-off-by: crynobone <crynobone@gmail.com>

.gitattributes

@@ -7,6 +7,7 @@
 /.coveralls.yml     export-ignore
 /.gitattributes     export-ignore
 /.gitignore         export-ignore
+/.php_cs            export-ignore
 /.scrutinizer.yml   export-ignore
 /.travis.yml        export-ignore
 /build.xml          export-ignore

.php_cs

@@ -0,0 +1,25 @@
+<?php
+
+$finder = Symfony\Component\Finder\Finder::create()
+    ->files()
+    ->in(__DIR__.'/src')
+    ->ignoreDotFiles(true)
+    ->ignoreVCS(true);
+
+return Symfony\CS\Config\Config::create()
+    ->level(Symfony\CS\FixerInterface::PSR2_LEVEL)
+    ->fixers([
+        '-psr0',
+        'concat_without_spaces',
+        'duplicate_semicolon',
+        'empty_return',
+        'extra_empty_lines',
+        'unused_use',
+        'single_array_no_trailing_comma',
+        'remove_leading_slash_use',
+        'remove_lines_between_uses',
+        'short_array_syntax',
+        'spaces_cast',
+        'whitespacy_lines',
+    ])
+    ->finder($finder);