The added path in cfg_model_model_estimation.m not same as repo name

[nbeliy]

Dear developpers,
It's almost not an issue, but nevertheless,
the easiest (and probably the standard) way to install the toolbox is to clone it into toolbox directory.
But in the config file the added path MSPM_toolbox do not corresponds to the default cloned directory name MSPM.
It's easy to correct, but may confuse inexperienced user (especially if you don't provide installation instructions).

An easy fix will be just retrieve the path to config file, and add it, so it will automatically adapt to any name of directory.