Function to retrieve contact maps from structures

[leandroradusky]

Having a protein structure, we will feed our neural networks with its contact map. The first functionality we should implement for this class is retrieving its contact map as a two-dimensional NumPy array, fulfilled with zeros and ones, based on a distance threshold, given as a parameter to the function.

The Bio (biopython) module would be useful to parse the PDB file and compute those distances.