iOS / PNChart

…art into openhood-independant-margins-bar-chart

…rrygdm-multiple-selection

PieChart: add updateData() method

PieChart: redraw chart if layout changed

Fix iOS version requirements in README

This is to support autolayout and constraints.

Resize layers for current bounds on layoutSubviews.
For that to work we need to have radiuses recomputed on each draw.

As a bonus you can now orverride `recompute` method to change
inner and outer radiuses. With possibility to change other attributes
in a subclass.

...to avoid confusion for people trusting the README.

Piechart labels filter based on values

I added this property because showing all labels, when there are a lot of small items in the dataset, is quite confusing.

Example:
piechart.labelPercentageCutoff = 0.05
hide all labels with value less than 5% (I use this most of the times).

Leii

Merge from origin

Add prefix/suffix public property for y label values

Make countingLabel show updated percent instead of absolute value

A radar chart is a graphical method of displaying multivariate data in
the form of a two-dimensional chart of three or more quantitative
variables represented on axes starting from the same point.

Too ugly that I can not stand with.