Allow JDFlipViewRelativeMargin to be configured

[cyrilchandelier]

This value should be configurable someplace in the component to enhance the rendering.

For instance with my custom design, the views are too close one from each other, I would like to set JDFlipViewRelativeMargin to something like 30%.

[johnboiles]

:+1: agree. I might give this a shot.

Another way to think about it could be to add two values that work in points instead of percentages:

//! Outer padding in points
@property UIEdgeInsets insets;
//! Spacing between numbers in points
@property CGFloat numberMargin;

What do you think about that instead of doing a percentage margin?

[calimarkus]

We can make two properties:

@property CGFloat relativeDigitMargin; @property CGFloat absoluteDigitMargin;

and then just use MAX(relative*width, absolute) as margin. Pull requests welcome.

[johnboiles]

Here you go! #42