Import libraries for linear regression

lin_reg_import.rs

// import rusty_machine for linear regression 
// as well as rust_machine Matrix and Vector as we need them for input 
use rusty_machine; 
use rusty_machine::linalg::Matrix; // surprise, Matrix is in linear algebra
use rusty_machine::linalg::BaseMatrix; // implement traits for matrix
use rusty_machine::linalg::Vector; 
use rusty_machine::learning::lin_reg::LinRegressor;
use rusty_machine::learning::SupModel; // this is extremelly important
// as this implement the traits to user predict and train
//use smartcore::metrics::*;
use rusty_machine::analysis::score::neg_mean_squared_error;
// import the reader 
use read_csv::read_housing_csv;