Fixed:

  - Error in add() where nil values were not being handled correctly with valid defaults
  - error in set() where components.minute could be set to seconds instead of minutes

Cleaned up code in set() to use the nil coalescing operator (??) for brevity

SwiftDate/SwiftDate.swift

@@ -329,12 +329,12 @@ public extension NSDate {
  */
  func set(#year: Int?, month: Int?, day: Int?, hour: Int?, minute: Int?, second: Int?, tz: String?) -> NSDate! {
  let components = self.components
- components.year = (year != nil ? year! : self.year)
- components.month = (month != nil ? month! : self.month)
- components.day = (day != nil ? day! : self.day)
- components.hour = (hour != nil ? hour! : self.hour)
- components.minute = (minute != nil ? minute! : self.second)
- components.second = (second != nil ? second! : self.second)
+ components.year = year ?? self.year
+ components.month = month ?? self.month
+ components.day = day ?? self.day
+ components.hour = hour ?? self.hour
+ components.minute = minute ?? self.minute
+ components.second = second ?? self.second
  components.timeZone = (tz != nil ? NSTimeZone(abbreviation: tz!) : NSTimeZone.defaultTimeZone())
  return NSCalendar.currentCalendar().dateFromComponents(components)
  }
@@ -394,13 +394,13 @@ public extension NSDate {
  */
  func add(#years: Int?, months: Int?, weeks: Int?, days: Int?,hours: Int?,minutes: Int?,seconds: Int?) -> NSDate {
  var components = NSDateComponents()
- components.year = years ?? years!
- components.month = months ?? months!
- components.weekOfYear = weeks ?? weeks!
- components.day = days ?? days!
- components.hour = hours ?? hours!
- components.minute = minutes ?? minutes!
- components.second = seconds ?? seconds!
+ components.year = years ?? 0
+ components.month = months ?? 0
+ components.weekOfYear = weeks ?? 0
+ components.day = days ?? 0
+ components.hour = hours ?? 0
+ components.minute = minutes ?? 0
+ components.second = seconds ?? 0
  return self.addComponents(components)
  }