title: How to properly use phpcs for checking all php files on project directory
body: <p>I want to perform a check for <strong>all</strong> php files in my project directory to see if they are compatible with PHP 7.</p>
  
  <p>I installed PHPCompatibility as a phpcs standard and I realised that variations such as .class.php, .lib.php .inc.php<br>
  were skipped using only <code>--extensions=php</code> or not specifying any <code>--extensions</code> as per the examples bellow</p>
  
  <p>1) No --extensions</p>
  
  <pre><code>phpcs -p -s -v --standard=PHPCompatibility  /Users/natalisilverio/Sites/php7/ --runtime-set testVersion 7.0  --report-file=phpcs-noExtensions.txt
  </code></pre>
  
  <p>2) --extensions=php</p>
  
  <pre><code>phpcs -p -s -v --standard=PHPCompatibility  /Users/natalisilverio/Sites/php7/ --runtime-set testVersion 7.0 --extensions=php --report-file=phpcs-phpExtensions.txt
  </code></pre>
  
  <p>3) Multiple --extensions</p>
  
  <pre><code>phpcs -p -s -v --standard=PHPCompatibility  /Users/natalisilverio/Sites/php7/ --runtime-set testVersion 7.0 --extensions=php,inc.php,lib.php,class.php --report-file=phpcs-multipleExtensions.txt
  </code></pre>
  
  <p>If I target a specific directory that has an .class.php file and set --<code>extensions=.class.php</code> as an extension I get it listed on my report</p>
  
  <pre><code>phpcs -p -s -v --standard=PHPCompatibility  /Users/natalisilverio/Sites/php7/ --runtime-set testVersion 7.0 --extensions=class.php --report-file=phpcs-classExtensions.txt
  </code></pre>
  
  <p>I have many 3rd party plugins and I cannot tell which variation they would be using, so I would like to know which is the correct way to correctly check my project folder <strong>recursively without setting multiple extensions</strong> variations for .php files  </p>