Update to work with python3 and geohash2

[djjavo]

Given that support for Python 2 will stop on the January 1, 2020. I have updated the code using an automated Python 2 to 3 code translation tool and altered the Geohash library to use geohash2 instead.

The code was tested on Python 3.6 with the following dependencies:

• NumPy >= 1.16.2
• Cython >= 0.29.6
• shapely >= 1.6.4.post2
• geohash2 == 1.1
• pandas >= 0.24.2
• scipy >= 0.20.3

A test was made on a trajectory dataset, where the md5 hashes of the dissimilarity matrices from both the old and new traj-dist packages were identical.

[bguillouet]

First sorry for the VERY late answer. I didn't know very well GitHub untill recently and i never look at this PR. This works perfectly, so thank you very much, for this 🙏. I merged it. .