[CLEANUP] Add PHP-CS-Fixer config file, ignore fixer cache and run fixer

.gitignore

@@ -1 +1,2 @@
-.DS_Store
+.DS_Store
+.php_cs.cache

.php_cs

@@ -0,0 +1,83 @@
+<?php
+/**
+ * This file represents the configuration for Code Sniffing PSR-2-related
+ * checks of coding guidelines and is based on a template from the news extension
+ * by Georg Ringer for the TYPO3 CMS.
+ *
+ * Install @fabpot's great php-cs-fixer tool via
+ *
+ *  $ composer global require friendsofphp/php-cs-fixer
+ *
+ * And then simply run
+ *
+ *  $ php-cs-fixer fix --config .php_cs
+ *
+ * For more information read:
+ * 	 http://www.php-fig.org/psr/psr-2/
+ * 	 http://cs.sensiolabs.org
+ */
+
+if (PHP_SAPI !== 'cli') {
+    die('This script supports command line usage only. Please check your command.');
+}
+// Define in which folders to search and which folders to exclude
+// Exclude some directories that are excluded by Git anyways to speed up the sniffing
+$finder = PhpCsFixer\Finder::create()
+    ->exclude('vendor/')
+    ->in(__DIR__);
+
+// Return a Code Sniffing configuration using
+// all sniffers needed for PSR-2
+// and additionally:
+//  - Remove leading slashes in use clauses.
+//  - PHP single-line arrays should not have trailing comma.
+//  - Single-line whitespace before closing semicolon are prohibited.
+//  - Remove unused use statements in the PHP source code
+//  - Ensure Concatenation to have at least one whitespace around
+//  - Remove trailing whitespace at the end of blank lines.
+return PhpCsFixer\Config::create()
+    ->setRiskyAllowed(true)
+    ->setRules([
+        '@PSR2' => true,
+        'align_multiline_comment' => [
+            'comment_type' => 'all_multiline',
+        ],
+        'array_syntax' => [
+            'syntax' => 'short'
+        ],
+        'binary_operator_spaces' => [
+            'default' => 'single_space'
+        ],
+        'concat_space' => [
+            'spacing' => 'one'
+        ],
+        'function_typehint_space' => true,
+        'hash_to_slash_comment' => true,
+        'lowercase_cast' => true,
+        'native_function_casing' => true,
+        'no_alias_functions' => true,
+        'no_blank_lines_after_phpdoc' => true,
+        'no_empty_statement' => true,
+        'no_extra_consecutive_blank_lines' => true,
+        'no_leading_import_slash' => true,
+        'no_leading_namespace_whitespace' => true,
+        'no_trailing_comma_in_singleline_array' => true,
+        'no_short_bool_cast' => true,
+        'no_singleline_whitespace_before_semicolons' => true,
+        'no_unused_imports' => true,
+        'no_unneeded_control_parentheses' => true,
+        'no_whitespace_in_blank_line' => true,
+        'ordered_imports' => true,
+        'phpdoc_no_empty_return' => true,
+        'phpdoc_no_package' => false,
+        'phpdoc_scalar' => true,
+        'phpdoc_trim' => true,
+        'return_type_declaration' => [
+            'space_before' => 'none'
+        ],
+        'self_accessor' => true,
+        'single_quote' => true,
+        'standardize_not_equals' => true,
+        'whitespace_after_comma_in_array' => true,
+    ])
+    ->setFinder($finder);