Fix linebreaks in Guidebook event export

We were converting newline characters to spaces, likely because the CSV export was breaking them somehow. Now that we use XLSX, all newline characters seem to work when uploaded to Guidebook.

uber/models/panels.py

@@ -69,7 +69,7 @@ def guidebook_data(self):
             'end_time': self.end_time_local.strftime('%I:%M %p'),
             'location': self.location_label,
             'track': self.track,
-            'description': normalize_newlines(description).replace('\n', ' '),
+            'description': description,
             }
 
     @property