[BUG] Small-worldness value is not saved properly

[xiaosonghe]

As one product of the GQI recon pipeline, Small-worldness for both binary and weighted format are saved in the .mat file. However when it is loaded into Matlab workspace, an error is displayed as it's value, and Matlab could not recognize this variable despite it is "in" the workspace. The error seems to be related to the "-" sign, somehow it is not recognized correctly by Matlab. Not sure if it's a cross-platform format issue (i.e., python to Matlab). This is not urgent.