Create count_obese_contacts.m

Uploaded code for Amr

 function returns a matrix 'number_of_obese_contacts'
 that has the number of obese contacts each person has at every timestep
 weight_over_time: entry (i,j) represents whether person i is obese at
 time j (entry in the matrix is one) or not (entry is zero)
 adj matrix, entry (i,j) represents whether person i know person j or not