Gillette Co. on Thursday unveiled a new top-of-the-line disposable razor as it tries to regain market share from rival Schick in the disposables market. The new Sensor 3 is a disposable version of Boston-basted Gillette’s Sensor blade and razor system.Aside from giving Gillette a higher-end product to compete with Schick’s Extreme 3, the new disposable will help Gillette use up Sensor production capacity that has been freed up as the company has tried to entice consumers to use the m...