Disabled application pool recycling, some fixes

• • HOTFIX * fixed a potential crash of myrtille services when sending a disconnect notification (#187, thanks gtmsew)
• the automatic application pool recycling is now disabled by default, and is not applicable if using the enterprise mode (this prevents enterprise sessions to be dropped unexpectedly!)
• if recycling is enabled, a new http session is now acquired on disconnect; this prevents a subsequent login failure (due to the old http session being invalid) without any error message