Upgrade and Fix tvb-gdist C++ Library

While running simulation on cortical surfaces we need to calculate geodesic distance as opposed to euclidean distance due to the shape of the cortical surface. The virtual brain uses geodesic_library for this calculation. The library implements the original paper in C++. The original source code can be found in Google Code Archive: https://code.google.com/archive/p/geodesic. tvb_geodesic repository implements a cython wrapper on top of the C++ code which then is released to Pypi (tvb-gdist) and conda-forge (Tvb Gdist).

However, the code is now outdated and users have reported various issues. In this project, we aim to update the code and fix those issues.