- add TUI

- add "subnet finder" - given a prefix, find the subnet of size S that contains address X.
-- if the existing libraries don't have an easy/fast way of doing this, try a binary search.

- add env vars to all args
- add ability to limit number of returned cidrs from split-cidr, split-nets
- add ability to support "address pools" - multiple networks specified at end, or a path to a "pool file" (one network per line)
- add VLSM spec to allow for e.g. `-s<N>[:<Y>]`, where Y would be an optional repeater
  e.g.:
	-s 25:3
		== -s 25 -s 25 -s 25
	-s 25:2 -s 25:3
		== -s 25:5
		== -s 25 -s 25 -s 25 -s 25 -s 25
	Ensure ordering is preserved/do not consolidate:
	-s 25:2 -s 24:2 -s 25:2
		== -s 25 -s 25 -s 24 -s 24 -s 25
		!= -s 25 -s 25 -s 25 -s 25 -s 24 -s 24 (that'd be -s 25:4 -s 24:2 explicitly)

- add option to consolidate subnets into minimum representation of pools/subnets. ("coalesce" operation)

- add NetBox integration?

- add table rendering for reserved networks
-- note that the IANA doesn't seem to include all? e.g. ff02:: etc.
-- ... that's because it's in a different registry:
	https://www.iana.org/assignments/ipv6-multicast-addresses/ipv6-multicast-addresses.xhtml
	https://www.iana.org/assignments/multicast-addresses/multicast-addresses.xhtml
	see https://www.iana.org/numbers "IP Address Allocations" section

- when checking/rendering reserved networks, currently the footnotes aren't returned.
-- netsplit.IANARegistryFootnote
-- encapsulated in the IANARegistry.Footnotes

- add new interface, Getter? different formatting?
-- (i forget what this was for. carving a smaller subnet out of a subnet?)