Fix IMU report

The order of acceleration and angular velocity fields are fixed so the
reported values are correct. The axis orientation is positive X pointing
right, positive Y pointing up, and positive Z pointing towards the user.

For the angular velocities, the following convention is used for the
names (following the right thumb rule):

Roll: rotation around X axis
Pitch: rotation around Y axis
Yaw: rotation around Z axis

The code has been tested by checking that the sign of the values are
consistent with the axis orientation when translating/rotating the
device.

References:
- https://gamedev.stackexchange.com/a/87178
- http://eleccelerator.com/wiki/index.php?title=DualShock_4#Report_Structure

ds4drv/device.py

@@ -41,12 +41,12 @@ class DS4Report(object):
                  "button_options",
                  "button_trackpad",
                  "button_ps",
-                 "motion_y",
-                 "motion_x",
-                 "motion_z",
                  "orientation_roll",
-                 "orientation_yaw",
                  "orientation_pitch",
+                 "orientation_yaw",
+                 "motion_x",
+                 "motion_y",
+                 "motion_z",
                  "trackpad_touch0_id",
                  "trackpad_touch0_active",
                  "trackpad_touch0_x",
@@ -181,13 +181,13 @@ def parse_report(self, buf):
             # Trackpad and PS buttons
             (buf[7] & 2) != 0, (buf[7] & 1) != 0,
 
-            # Acceleration
+            # Orientation
             S16LE.unpack_from(buf, 13)[0],
             S16LE.unpack_from(buf, 15)[0],
             S16LE.unpack_from(buf, 17)[0],
 
-            # Orientation
-            -(S16LE.unpack_from(buf, 19)[0]),
+            # Acceleration
+            S16LE.unpack_from(buf, 19)[0],
             S16LE.unpack_from(buf, 21)[0],
             S16LE.unpack_from(buf, 23)[0],