Description of enhancement:

For the networking questions in fusor-installer, add additional sanity checks.

Version-Release number of selected component (if applicable):

RHCI 6.0, ISO Media ID 1437667080.278333

Additional info:

The potential changes fall into 2 classes:
A) Validation of the individual item
B) Validation between multiple items.  This could potentially be done as an optional step or at the beginning of "Proceed with configuration"

Some ideas:
1) Verify IP address, network mask, and address range all make sense together
2) Verify DHCP range end >= DHCP range start
3) Verify formats more specifically.  192.168.1.1.1 was accepted without complaint