Ternary-diagram

- When a TernaryDiagram instance is created so that multiple ternary diagrams can be drawn, it can take matplotlib.pyplot.figure and matplotlib.pyplot.axis objects as arguments.
- Changed the axis specification to be more specific.
- The position of the axis labels has been fine-tuned.
- Updated the example.
- Added an example on how to draw multiple ternary diagrams.

Add badges.

* Add` DESCRIPTION`.
* Modify `license`.

This is a initial version that is registered in PyPI.

Change class name from `ternary_diagram` to `TernaryDiagram`.

To deal with the multiple input when zorder is specified in scatter.
And modify .gitattributes.