[Bugfix] Merge traces treating overlaps as data instead of gaps

Could not open the Pickwindow on some stations. 
Gaps were merged so that overlapping values were marked as gaps, which lead to an error when those traces were processed. Method 1 takes data from traces instead, see https://docs.obspy.org/packages/autogen/obspy.core.trace.Trace.__add__.html

pylot/core/util/utils.py

@@ -870,7 +870,7 @@ def merge_stream(stream):
     if gaps:
         # list of merged stations (seed_ids)
         merged = ['{}.{}.{}.{}'.format(*gap[:4]) for gap in gaps]
-        stream.merge()
+        stream.merge(method=1)
         print('Merged the following stations because of gaps:')
         for merged_station in merged:
             print(merged_station)

pylot/core/util/widgets.py

@@ -1233,7 +1233,7 @@ class PylotCanvas(FigureCanvas):
         gaps = st_select.get_gaps()
         if gaps:
             merged = ['{}.{}.{}.{}'.format(*gap[:4]) for gap in gaps]
-            st_select.merge()
+            st_select.merge(method=1)
             print('Merged the following stations because of gaps:')
             for merged_station in merged:
                 print(merged_station)