Upgraded to Xcode 5.1
Updated storyboard and layout constraints
Return CGColorRef from 'popUpViewColor' in 'ASValuePopUpView' rather than UIColor

Still return a UIColor from ‘ASValueTrackingSlider’.
The rational will become clearer in a bit - will need the ability to
override alpha value from ‘ASValuePopUpView’ and set it to 1.0.
Removed redundant method calls
Add delegate to ASValuePopUpView
Manually set properties in 'set-up' rather than call setters to avoid repeatedly recalculating popUpViewSize etc
Removed 'offset:(CGFloat)offset' argument from 'setPopUpViewAnimatedColors' method
Added NSString *const FillColorAnimation
Increased spacing between UISliders
Remove property definition (use method call instead)
Changed default popUpViewColor
Implemented autoAdjustTrackColor

When animated popUpView colours are used, ‘minimumTrackTintColor’ is
continuously updated with the popUpView color.
Declared 'autoAdjustTrackColor' property
Added comments
Changed popUpViewAnimatedColors of slider2
Removed old comment
Reordered method declaration
Refactored 'setPopUpViewAnimatedColors' adding better comments
Moved 'show' and 'hide' methods to ASValuePopUpView class
Renamed methods