It's mostly used for Serializable and in other cases where one needs to
estimate binary-encoded size of the stucture. This also simplifies future
removal of the Size() from Serializable.
The logic here is that we'll have all binary encoding/decoding done via our io
package, which simplifies error handling. This functionality doesn't belong to
util, so it's moved.
This also expands BufBinWriter with Reset() method to fit the needs of core
package.
Fixes things like:
* exported type/method/function X should have comment or be unexported
* comment on exported type/method/function X should be of the form "X ..."
(with optional leading article)
Refs. #213.
* added account_state + changed ECPoint to PublicKey
* account state persist
* in depth test for existing accounts.
* implemented GetTransaction.
* added enrollment TX
* added persist of accounts and unspent coins
* bumped version -> 0.32.0
