Add missing require for macaddress

This fixes the error "Could not retrieve macaddress: uninitialized constant
Facter::Util::IP"
Call correct function on IP in NetMask

This fixes the error "Could not retrieve netmask: wrong number of arguments (1
for 0)"
Merge pull request #392 from pcarlisle/fix-nettools

Fix nettools
Merge branch '1.6.x' into 1.7.x