Among the many new features introduced in iOS 7, the new Control Center was one of the most useful upgrades. Users no longer need to open the settings app to make very small changes such as toggling bluetooth or increasing the brightness. However, one thing which Apple missed out on is the ability to scan and connect to WiFi whenever the user demands it without having to open the settings app.
Currently, a user is offered to allow the iPhone to ask to join networks. But the popup doesn't always come at the right time. Additionally, it's better to keep that toggle turned off to help save battery.
Jailbroken iPhone users are offered a solution by @Bensge, one of the developers who worked on Velox. Bensge released a tweak called WiPi some time ago in Cydia, before the introduction of iOS 7. WiPi has been updated to take advantage of the Control Center.