made cell layout adjustments
add segue identifier to current segues in interface builder and check for them in prepareSegue
add detail view in interface builder and pass a SpotLibrary object and the ID of the selected spot to this view

- added new SpotDetailViewController
- the segues are more check-heavy now that there are multiple kinds of segues forwards and backwards
remove unnecessary SpotLibrary initialization in searchForNewSpotsController

- removed the constructor here because this value is set by yourSpotsTableViewController anyway before the segue into searchForNewSpots is performed. When I wrote this I didn't yet know that you could add a ! at the end of a class member and not have to initialize it
keep track of the last time the application was closed, refresh information if the app is being opened in a new hour

- added a new value being saved to NSUserDefaults to keep track of the last hour the app was closed, which is compared to the current hour when the app is opened again