Add geographic point object

[flohorovicic]

Add an object to handle points in geographic coordinate systems

[AlexanderJuestel]

Currently, we are not creating any new classes to edit the data we obtain from input files. This works pretty well as we can use the full power/functionalities of DataFrames, GeoDataFrames and numpy.ndarrays and just return DataFrames in the end that can directly be read into GemPy.

However, it would still be interesting to explore how we could such a class in GemGIS.

@flohorovicic, moving this to GemGIS as well to clean up GemPy a little?

[AlexanderJuestel]

GemGIS does not work with single point objects. It works with NumPy arrays, GeoDataFrames and DataFrames. Therefore, this feature is not needed at the moment.