Update readme

Begin logging
Account for fb2 books without covers

lector/widgets.py

@@ -20,6 +20,7 @@
 
 import os
 import uuid
+import logging
 
 from PyQt5 import QtWidgets, QtGui, QtCore
 
@@ -28,6 +29,8 @@ from lector.sorter import resize_image
 from lector.threaded import BackGroundTextSearch
 from lector.contentwidgets import PliantQGraphicsView, PliantQTextBrowser
 
+logger = logging.getLogger(__name__)
+
 
 class Tab(QtWidgets.QWidget):
     def __init__(self, metadata, main_window, parent=None):