Cleaned up some of the docs and added the new functions int_var_domain, set_int_var_domain, add_leq, and require now that all variables be given names

tests/sat_parameters.rs

@@ -3,10 +3,10 @@ use cp_sat::proto::{CpSolverStatus, SatParameters};
 
 #[test]
 fn simple_sat_parameters() {
-    let mut model = CpModelBuilder::default();
-    let x = model.new_bool_var();
-    let params = SatParameters::default();
-    let response = model.solve_with_parameters(&params);
-    assert_eq!(response.status(), CpSolverStatus::Optimal);
-    let _x_value = x.solution_value(&response);
+  let mut model = CpModelBuilder::default();
+  let x = model.new_bool_var("x");
+  let params = SatParameters::default();
+  let response = model.solve_with_parameters(&params);
+  assert_eq!(response.status(), CpSolverStatus::Optimal);
+  let _x_value = x.solution_value(&response);
 }