Version 1.5.5

Highlight: New Progress ring style gradient added!

• Added new progress ring style gradient which allows for drawing a gradient inner ring given some colors.
• Added 4 new properties to UICircularProgressRingView which are used to determine the look of the gradient when drawing
• Added new enumeration type UICircularProgressRingGradientPosition to determine position of gradient for drawing purposes
• Updated docs to reflect these new changes

Breaking changes in 1.5.5