Make verbose an argument for the fit function

tests/binary-1.rs

@@ -23,5 +23,5 @@ fn binary_1() {
     model.observe(&["benjamin"], &["audrey"], 6.0);
     model.observe(&["benjamin"], &["audrey"], 7.0);
 
-    model.fit();
+    model.fit(true);
 }

tests/kickscore-basics.rs

@@ -27,7 +27,7 @@ fn kickscore_basic() {
     model.observe(&["Jerry"], &["Tom"], 3.0);
     model.observe(&["Jerry"], &["Tom", "Spike"], 3.5);
 
-    model.fit();
+    model.fit(true);
 
     let (p_win, _p_los) = model.probabilities(&["Jerry"], &["Tom"], 4.0);
 

tests/nba-history.rs

@@ -73,7 +73,7 @@ fn nba_history() {
         model.observe(&[&winner], &[&loser], t);
     }
 
-    model.fit();
+    model.fit(true);
 
     let (p_win, _) = model.probabilities(
         &["CHI"],