Updates (#71)

* further optimizations

* abstract `Chart` class

* (add) `PieChart` + example

* fix wrong labeling on x and y axis

* + area charts

* update readme

* merge

* cleanup

* rename variable in example

* (up) chart properties

* (up) data tooltip

* (add) ec_utilities class

This class will store all shared methods for plotting

* (up) Legend

* (up) data tooltip

* (add) canvas, grid box and plotbox

* (add) function class

* (rem) SampledAxis class

* (remv) Pair class

* (up) Point logic

* (up) chart properties

* (up) chart class

* (up) remove scenes, implement Plotters

* (up) plugin

* (up) properties

* (rmv) unused classes

* (up) icons

* (up) plotters and chart

* (up) examples

* (up) examples

* (up) Pie and Bar plotters

* (up) SimplePlot example

Author: fenix-hub