Update: Network additions and improvements, minor documentation comment clean ups.

Update: Network additions and improvements, minor documentation comment clean ups.

Add f_network_is_ip_address() along with appropriate unit tests.
The unit test are not as thorough as they could be.
I did not fully review the IPv6 standard, which has a rather absurd design.
There are likely things that I do not yet know about that are not supported.
Specifically do not support port number on any IPv6 address without brackets.
(The IPv6 address notation standard is horribly written.)