Fixes #7 by checking the signal stack in the progress bar function. The

idea to check the signal at that place is that most of the step
involving long computation time call regularly this function to update
the progress bar

python/orgasm/utils/_progress.pyx

 # cython: language_level=3
+from cpython.exc cimport PyErr_CheckSignals
+
 
 cpdef object progressBar(object pos,
                   off_t maxi,
@@ -103,6 +105,9 @@ cpdef object progressBar(object pos,
             
         diese[fraction]=b'#'
         spaces[50 - fraction]=b' '
+        
+        # Added to check if signal (Ctrl-C) are send to the program
+        PyErr_CheckSignals()
 
     else:
         cycle+=1