build specification tests function and vector of names
[test_func,name_test]=auto_test(auto_ names,auto_ltest,nobs)
* auto_names = the tlist that associates a name to each specification test function
* auto_ltest = the list of options provided by the user (default: an empty list)
* nobs = # of observations
* test_func = the function which gathers the specification tests used by automatic()
* name_test = the name of the specification tests which will be used for the printings