Incredibly useful categories that I use in all my Xcode projects!
pod 'BDGCategories'
##Examples
NSDate
Various date check methods
NSDateFormatter
Thread-safe generation of unique dateformatters
NSNotificationCenter
Add only unique observers
NSObject
Set values with dictionary safely withouth crashing
UIImage
Resize/Scaling, Rotation, Blur
UIView
Rounded corners, choose your own corner!