nsort sorts namespaces and pages together

When nsort sorting option is switched on, namespaces and pages on the same index level are sorted together.
I use it with msort option as well.
Original behaviour sorted namespaces first and then sorted pages were added.
Maybe new sorting option can be added for this mode.
Yes MI are my initials - I have just marked the code I have changed for myself.
I do not need any authorship notes...