Dev Docs: Describe Initial Peer Discovery & DNS Seeds

[harding]

Preview: http://dg0.dtrt.org/en/developer-guide#p2p-network

• Revise P2P Networking section to provide a more detailed description
  of initial peer discovery and DNS seeds.
• Tweak autocrossref.rb to allow term blacklisting. Then use this new feature
  to prevent cross referencing "address" in "IP address" to the
  definition of Bitcoin P2PKH/P2SH addresses. This avoids a bunch of
  manual "norefs".

@instagibbs: this revises some of your text; please let me know if you see anything I missed.

Note: this is the first of several expansions I plan to make to the P2P Networking and Operating Mode sections over the next couple weeks. I'm breaking them up into medium-sized commits to hopefully make reviewing them less painful than my normal giant commits. :-)

[gmaxwell]

Should probably also mention the static table of addresses and the ability to manually provision peers.

[harding]

@gmaxwell good idea, thanks! Done in commit 4553439 and preview updated.

[saivann]

LGTM, thanks! Clever trick in the autocrossref plugin :) .

I've noticed that mainnet and testnet is not consistently uppercased or lowercased everywhere, I can take care to push a commit to lowercase them all once this is merged (it seems lowercase is used more often in devel-reference and devel-examples).

[harding]

@saivann thanks! I agree with lowercasing mainnet/testnet. I'm not actually sure how they started getting uppercased.

In the absence of critical feedback, this pull will be merged Wednesday.

[instagibbs]

I like the changes, and especially how you are careful to distinguish the consensus rules from p2p protocol, with representative examples core/bitcoinj.

LGTM

[harding]

@instagibbs thanks! I've got some more network section changes coming in a separate branch---over 300 lines already written. :-)

[instagibbs]

putting the rest of us to shame :) I wonder how much of my original writing is left at all! Great stuff.

[saivann]

@instagibbs You're welcome to assign yourself to any new task ;) Thanks for reviewing!