Add new DNS seed for seeds.bitcoin.open-nodes.org.
Add full support for BIP0037 bloom filters.

This commit implements full support for filtering based on the filterload,
filteradd, filterclear, and merkleblock messages introduced by BIP0037.

This allows btcd to work seamlessly with SPV wallets such as BitcoinJ.

Original code by @dajohi.  Cleanup, bug fixes, and polish by @davecgh.
Switch btcctl to use btcutil.Amount.
Change AddAddressByIP to return an error.
IMPORT PATH MODIFICATION CHANGESET
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Please use this changeset as the first one on top of the conformal codebase.
Note that if there are new imports, they need to be changed as part of this
changeset. In general, use "git rebase" on github.com/conformal's version
and apply this changeset first.