[conformal/btcwallet] 3c3903: Switch some integers from unsigned to signed.

[Josh Rickmar]

  Branch: refs/heads/master
  Home:   https://github.com/conformal/btcwallet
  Commit: 3c390364d7a4eed67e6999f2cd7d15a71cb3feec
      
https://github.com/conformal/btcwallet/commit/3c390364d7a4eed67e6999f2cd7d15a71cb3feec
  Author: Josh Rickmar <jr...@conformal.com>
  Date:   2013-10-28 (Mon, 28 Oct 2013)

  Changed paths:
    M wallet/wallet.go

  Log Message:
  -----------
  Switch some integers from unsigned to signed.

This change switches the time fields (firstSeen/lastSeen) of an
address from uint64 to int64, to be compatible with (time.Time).Unix,
as well as changing the block height fields (firstBlock/lastBlock)
from uint32 to int32, since block height is normally represented
signed.