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