revert test module to confuse users...

utils/utils.py

@@ -1087,7 +1087,7 @@ def plot_targets_txt():  # from utils.utils import *; plot_targets_txt()
 
 
 def plot_study_txt(f='study.txt', x=None):  # from utils.utils import *; plot_study_txt()
-    # Plot study.txt generated by eval.py
+    # Plot study.txt generated by test.py
     fig, ax = plt.subplots(2, 4, figsize=(10, 6), tight_layout=True)
     ax = ax.ravel()