We add a Token class to Tx, which adds an easy to use API when compared
to the plain iterator. The main point of the API chosen is to make sure
we don't do unneeded parsing or copying for tokens unless needed.
Additionally refactor the ValidationPrivate::UnspentOutput class to
inherit from the Tx::Output class in order to avoid lots of duplicated
logic on handling the data.
This introduces a new BlockHeader helper class which Block and
MutableBlock can both produce, which helps a lot of methods to
be ported to no longer be dependent on us using a MutableBlock
object, which is too costly to use when we have no intention
to alter the block.
The CashToken bitfield now is more usable without magic numbers and we
have a bunch of documentation about what the fields mean.
Also remove unused variable.
This makes the Tx::nextOutput() and similar methods work properly when a
cashToken is encoutered.
For now we just add a simple bool on the output, this may be replaced
with more rich data if that turns out to be needed by the API users.
As we moved most of the creation of a BufferPool to be via the
Streaming::pool() method, which uses a thread-local, it makes sense
to start cleaning up the design and make it more modern C++.
The above mentioned method would return a reference and you'd see
loads of places use `auto &pool =` which is less than ideal.
As the number of places where we actually instantiate a BufferPool
goes down, the usage of some sort of smart pointer makes more sense.
This now makes all APIs use BufferPool be wrapped in a shared_ptr.
tomFlowee
John Galt