* Change makeseeds.py to use masternode list as input instead of DNS seed dump
* Allow 4 nodes per ASN
Lift the limitation a bit so we get more entries
* Update nodes_main.txt and nodes_test.txt
Generated with makeseeds.py based on current masternode lists
* Fix comment about the source of the seed nodes and use masternodelist rpc
* Use fixed OpenDNS servers for ASN filtering
This makes it possible for a node with `-onlynet=tor` to bootstrap
itself.
It also adds the base infrastructure for adding IPv6 seed nodes.
Also represent IPv4 fixed seed addresses in 16-byte format.