Add start of omega period to measured omegas

This fixes an issue introduced in #786.

We were missing the start of the omega period. This was not an issue
if the start of the omega period was 0, but it was an issue otherwise,
and likely caused some bad results.

Fixes: #811

Signed-off-by: Patrick Avery <[email protected]>

Author: psavery

hexrd/instrument/hedm_instrument.py

@@ -1770,7 +1770,10 @@ def pull_spots(self, plane_data, grain_params,
                     frame_indices = [
                         ome_imgser.omega_to_frame(ome)[0] for ome in ome_eval
                     ]
-                    ome_edges = np.array(frame_indices) * delta_ome
+                    ome_edges = (
+                        np.array(frame_indices) * delta_ome +
+                        np.degrees(ome_period[0])
+                    )
 
                     if -1 in frame_indices:
                         if not quiet: