Introduction of a param_dic parameter on plot_function that allows for specific parameters definitions for that curve only without changing the full Chart.
Also moved the label identier string to a parameter on this dicionary so it can be called without specifying a label name.
Restructured some functions in smaller pieces and changed it so they can work with data in the new format.
Main way to use it will be with the new plot_function but old functions support is requiered through structure_datas (WIP)
* Fixed ScatterChart to work like LineChart when are_values_columns is true
* Fixed labeling spaguetti and added offset.
* Fixed indentation to match GDScript style guide
* Fix distances calculations
Note that I removed the origin_at_zero conditional at calculate_coordinates because I already fix y_margin_min to 0 at structure_datas.
* Add missing features to ScatterChart
I added the missing features from LineChart to ScatterChart (like treshold and some properties) in preparation to creation of a Parent Class common to both. This way the changes can be traced easily.
* Add BaseClass for Scatter and Line Charts
* Changes to property_list getter
* Rename ScatterChartBase.gd to scatter_chart_base.gd
* Filenames changed to match GDscript Style Guide
From Godot so it doesn't break the links.
* Fixed some dependencies on chart and chart2D
