Add new widgets to README and examples.

Author: Zannick

README.rst

@@ -58,7 +58,9 @@ of widgets:
  - `FileTransferSpeed <http://progressbar-2.readthedocs.io/en/latest/_modules/progressbar/widgets.html#FileTransferSpeed>`_
  - `FormatCustomText <http://progressbar-2.readthedocs.io/en/latest/_modules/progressbar/widgets.html#FormatCustomText>`_
  - `FormatLabel <http://progressbar-2.readthedocs.io/en/latest/_modules/progressbar/widgets.html#FormatLabel>`_
+ - `FormatLabelBar <http://progressbar-2.readthedocs.io/en/latest/_modules/progressbar/widgets.html#FormatLabel>`_
  - `Percentage <http://progressbar-2.readthedocs.io/en/latest/_modules/progressbar/widgets.html#Percentage>`_
+ - `PercentageLabelBar <http://progressbar-2.readthedocs.io/en/latest/_modules/progressbar/widgets.html#PercentageLabelBar>`_
  - `ReverseBar <http://progressbar-2.readthedocs.io/en/latest/_modules/progressbar/widgets.html#ReverseBar>`_
  - `RotatingMarker <http://progressbar-2.readthedocs.io/en/latest/_modules/progressbar/widgets.html#RotatingMarker>`_
  - `SimpleProgress <http://progressbar-2.readthedocs.io/en/latest/_modules/progressbar/widgets.html#SimpleProgress>`_

examples.py

@@ -177,6 +177,17 @@ def multi_progress_bar_example(left=True):
             time.sleep(0.02)
 
 
+@example
+def percentage_label_bar_example():
+    widgets = [progressbar.PercentageLabelBar()]
+    bar = progressbar.ProgressBar(widgets=widgets, max_value=10).start()
+    for i in range(10):
+        # do something
+        time.sleep(0.1)
+        bar.update(i + 1)
+    bar.finish()
+
+
 @example
 def file_transfer_example():
     widgets = [