Plotille

* 2d91a7b - Drop python 2.7 support (52). We no are without any dependencies!
* 8bb6e0e - Add support for drawing histogram with aggregated (buckets + counts) data (51) by Kami . Many thanks! :tada:
* 589fe49 - Some extensions to the readme

I knew, there was a reason for the full urls ... pypi.

- Fix color codes (42)
- Consistent naming for named foreground / background colors.
- *breaking* change in Dots, Canvas and Figure: a `color_kwargs` argument is introduced to add kwargs to the color function.
The `color_mode` argument is `mode` in most cases now.
- Improve rendering performance (43)
- Images as binary braille dot in Canvas or heatmaps / images with background colors in Canvas / Figure
- CI now in Github

* Add examples.
* Allow marker characters for plot and scatter.
* Allow to write text inside the canvas.
* Add ellipse and circle data generation.
* Add vertical and horizontal lines for figures.
* Add vertical and horizontal rectangles for figures.
* Allow to customize X and Y ticks via callbacks.
* Improve docs.
* Respect NO_COLOR and FORCE_COLOR.

* e7b43e4 - Fix over/underflow with numpy.int16 (36)