#23 Nmap improvements

[Joseph Turley]

I'm sure it's probably in the works, but a nicer nmap
interface would be nice, especially including something
for entering a wider range of subnet masks and ranges
of ip addresses to scan.

Perhaps along these lines would be a checkbox option of
whether or not you want to delete the current
information for hosts being scanned. I know you took
this out of earlier builds, but I'd recommend making it an
optional thing.