Merge branch 'master' into develop

* master:
  Update readme
opcache_compile_file not available in PHP5.3/PHP5.4. Fixes #5
Merge branch 'master' of github.com:SchumacherFM/Magento-OpCache into develop

* 'master' of github.com:SchumacherFM/Magento-OpCache:
  check if apcu is installed
Merge branch 'develop'

* develop:
  opcache_compile_file not available in PHP5.3/PHP5.4. Fixes #5