MoveDifferential: use gyro for better accuracy (#705)

Author: dwalton76

debian/changelog

@@ -3,6 +3,8 @@ python-ev3dev2 (2.1.0) UNRELEASED; urgency=medium
   [Daniel Walton]
   * RPyC update docs and make it easier to use
   * use double backticks consistently in docstrings
+  * MoveDifferential use gyro for better accuracy. Make MoveTank and
+    MoveDifferential "turn" APIs more consistent.
 
   [Matěj Volf]
   * LED animation fix duration None
@@ -12,7 +14,7 @@ python-ev3dev2 (2.1.0) UNRELEASED; urgency=medium
   * Add "value_secs" and "is_elapsed_*" methods to StopWatch
   * Rename "value_hms" to "hms_str". New "value_hms" returns original tuple.
   * Fix bug in Button.process() on Micropython
-  
+
   [Nithin Shenoy]
   * Add Gyro-based driving support to MoveTank
 

ev3dev2/__init__.py

@@ -142,6 +142,12 @@ def library_load_warning_message(library_name, dependent_class):
 class DeviceNotFound(Exception):
     pass
 
+class DeviceNotDefined(Exception):
+    pass
+
+class ThreadNotRunning(Exception):
+    pass
+
 # -----------------------------------------------------------------------------
 # Define the base class from which all other ev3dev classes are defined.
 
@@ -214,7 +220,7 @@ def __str__(self):
             return "%s(%s)" % (self.__class__.__name__, self.kwargs.get('address'))
         else:
             return self.__class__.__name__
-    
+
     def __repr__(self):
         return self.__str__()