hostnames can end with a . (and actually always do, it's just usually implied), so allow that here. Fixes wrong input validation in parts of nsupdate GUI, among other things.
+ is a valid character in some dynamic DNS providers' usernames. Fixes #3912
Prevent Internal Server Error if range is backwards

Fixes redmine #3950 - ip_range_to_subnet_array can easily swap the input parameters if the caller has passed/entered them the wrong way around. That is both friendly to the caller and ensures that a hostile caller can't blow up the routine.
This patch is for master (2.2)
remove the command number shown in the shell prompt, it's a pointless
waste of screen space
Encode values before displaying them back to the user in notification settings
Merge pull request #1313 from phil-davis/patch-9

Prevent Internal Server Error if range is backwards