strtr faster than str_replace (maybe)
speed optimization
remove admin directory, mv config.php to root dir
add try/catch to email sending on registration
add some infos on the sysconfig page
put admin menus in footer, remove php sql logos, add github logo

Note : the js/common.js was not minified. It's a deletion so we don't
care.
Merge branch 'next'

* next:
  put admin menus in footer, remove php sql logos, add github logo
  add some infos on the sysconfig page
  add try/catch to email sending on registration
  remove admin directory, mv config.php to root dir
  speed optimization
  strtr faster than str_replace (maybe)