This commit moves btcd view away from using the deprecated
callbacks onBlockConnected/Disconnected, and instead use
onFilteredBlockConnected/disconnected.
This commit also implements the sending of disconnected blocks
over the staleBlocks channel. To send these blocks, the
blockEventQueue is used to ensure the ordering of blocks are
correctly kept.
It also changes the way filter updates are handled. Since we
now load the tx filter to the rpc server itself, we can call
RescanBlocks instead of manually filtering blocks. These
rescanned blocks are also added to the blockEventQueue,
ensuring the ordering is kept.
This commit fixes a possible race condition wherein a call to
FilterBlock after a call to UpdateFilter would result in the call to
FilterBlock not yet using the updated filter. We fix this by ensuring
the internal chain filter is updated by the time the call to
FilterBlock returns.
This commit adds the first concrete implementation of the
chainview.FilteredChainView interface. The implementation of this
interface, BtcdFilteredChainView is backed by a web sockets connection
to an active btcd instance.
