don't make API calls if input params are null or empty
minor cleanup
added black and gold star icons for favoriting resorts
first pass at FavoriteResortsManager class
added insertFavoriteResort to FavoriteResortsManager to support re-ordering favorites
removed unused import of SnoCountryClient.h
factored out favorite resorts to use FavoriteResortsManager class
added favorite button to EditResortCell