Added signal catching and handling in C and Cython

python/obitools3/commands/export.pyx

@@ -14,6 +14,8 @@ from obitools3.apps.optiongroups import addMinimalInputOption, \
 import sys
 import io
 
+from cpython.exc cimport PyErr_CheckSignals
+
 __title__="Export a view to a different file format"
 
 
@@ -66,6 +68,7 @@ def run(config):
     
     i=0
     for seq in iview :
+        PyErr_CheckSignals()
         if pb is not None:
             pb(i)
         try: