Added OBIView_line_selection class to make new line selections

associated with the view to clone, and improved and renamed method
closing a view

python/obitools3/commands/grep.pyx

@@ -75,10 +75,10 @@ def run(config):
     # Create output view with the line selection
     oview = d.new_view(config['obi']['outputview'], view_to_clone=iview, line_selection=selection, comments="obi grep: "+config['grep']['predicate']+"\n")
 
-    print(oview.__repr__())
+    repr(oview)
 
-    iview.save_and_close()
-    oview.save_and_close()
+    iview.close()
+    oview.close()
     d.close()
     
     print("Done.")