cgre-aachen/gempy: GemPy 2.2.0

This release does focused on polishing and deprecating a lot of code that it was half done (like the new 2d and 3d visualization)

• Moving docs building to travis
• Improved fixtures of pytest
• Pyvista is the default 3d render for gempy
• Adding restricting wrapper to better define the user API
• Added the class Stack (with features for each item) that encapsulates Series and Faults
• Topography and masked marching cubes have been fixed and consolidated
• Plots have vertical exaggeration finally
• Added (basic) probability examples
• Fixed all the requirements issues and better installation description
• Docs rework and added sphinx-gallery https://docs.gempy.org/

• Addedgempy.plot.plot_ar for direct communication with RexOS for visualizing the models in AR
• Refactoring of gempy's API
• Spline interpolation for 2D sections @Japhiolite
• Tweak palettes
• Refactoring of some internal classes
• Reworked docker