New: add switch button on/off

htdocs/langs/en_US/paypal.lang

htdocs/langs/fr_FR/paypal.lang

htdocs/lib/ajax.lib.php

htdocs/lib/functions.lib.php

htdocs/paypal/admin/import.php

htdocs/paypal/admin/paypal.php

htdocs/paypal/lib/paypal.lib.php

htdocs/theme/auguria/img/switch_off.png

htdocs/theme/auguria/img/switch_on.png

htdocs/theme/bureau2crea/img/switch_off.png

htdocs/theme/bureau2crea/img/switch_on.png

htdocs/theme/eldy/img/switch_off.png

htdocs/theme/eldy/img/switch_on.png

htdocs/theme/freelug/img/switch_off.png

htdocs/theme/freelug/img/switch_on.png

htdocs/theme/yellow/img/switch_off.png

htdocs/theme/yellow/img/switch_on.png