Getting a campsite reservation at Yosemite National Park is already difficult, but now it appears scalpers are snatching up the online reservations and selling them at a huge profit.  According to the "Sacramento Bee," the problem has become so bad that park officials are aggressively trying to shut down the illegal operators who try to resell the reservations on websites such as Craigslist.   The 900 Yosemite campsites that can be reserved in advance cost 20-dollars a night, but park officials say scalpers are selling them for up to 150-dollars a night.