Add QSPCount method to Science

Added a method in Science.hpp which takes 2 tracers and returns a quantitative scatter plot of their values. The user can specify in spins.conf the 2 tracers to use, the min/max values of the first/last bin respectively, the number of bins in each direction, and the filename to save the results to. A matlab script is included which correctly interprets the csv file in accordance with the names used in the config file. An example usage of the method can be found in the derivatives case.