Add Isolated Location option and option to created RIF (Reclearing In Flight)

Add the possibility to mark location as an Isolated (eg. no alternates, instead 2 hours of holding fuel at 1,500ft) and RIF along with this so you can divert to an already pre planned airport on preplanned route in case the weather at final destination would get worse. With this the GO/NO GO point at which you have to decide if you can continue to destination or you will need to fly to diversion field. As of now SB only allows 90 minutes of reserve fuel so I had to use the EXTRA fuel option to do such a thing.