Add FAS GoF code to GMSVToolkit

[fabiolsilva]

Integrate BBP's fas_gof module into the GMSVToolkit. This code should be added to the stats folder and should allow uses to specify two sets of smc8 files and a station list. The code will then create residuals files from these two datasets that can be used to plot a FAS GoF plot. Include interface so that users can invoke this code from the command-line. Also add options that enable users to specify seismogram prefixes and suffixes in order to provide enough flexibility. Include unit test to make sure code works as expected.