Enable the IsStandard check.

Previously, IsStandard always returned true.  Now, only return true if
the script can, indeed, be parsed as standard script.  Name prefixes are
stripped before attempting that.
Keep unspendable scripts out of the UTXO set.

Scripts that start with OP_RETURN are unspendable.  Detect those and
don't include them into the UTXO set.
Implement SendMoney for multiple recipients.

Rewrite the wallet sending functions a bit to simplify sending to
multiple recipients.
Handle OP_RETURN tagging in the RPC interface.

Allow adding an OP_RETURN output via a fifth, optional argument to
"sendtoaddress".  Display such OP_RETURN tags in decoded transactions.
Update IsStandard to accept tagging transactions.

In particular, allow tagging after the hardfork (not necessary, but
ensures that no clients are around that still include the outputs into
the UTXO set), for up to 100 characters of length and with 0.01 HUC
locked.
Disallow non-Namecoin tx with name outputs.

This is currently still allowed, but will be disallowed with the
upcoming fork.  It is something that isn't done by the official client
anyway.
Add block height to coinbases.  (BIP 30)

The block height in the coinbase prevents non-unique coinbase tx from
being generated.  No checks for BIP30 are done, though.
Disallow auxpow blocks that have an auxpow themselves.

This is a strange situation, but one that is currently allowed.  Forbid
it in the upcoming softfork.
Merge pull request #89 from domob1812/op-return

Enable storing "tags" to transactions with OP_RETURN scripts.
Merge pull request #92 from domob1812/txversion

Fix some "strange situations" in the upcoming fork.
Merge pull request #93 from domob1812/no-spawn-death

Disable spawn area death.