View source for SIP4-Optional-Input-Value

<div align="center">
    <h1>Snowblossom Improvement Proposal 4</h1>
    <h2>SIP4: Add optional Transaction Input</h3>
</div>
= Change =

In this change, we add an optional field to TransactionInput for the value of the input.
If it is set (non-zero) transaction validation will ensure that it accurately represents what is happening in the transaction.
Validation will fail if it is set (non-zero) and is incorrect.

This change makes it so that an offline transaction signer can have a more complete view of a transaction before signing it.  This also enabled the Rosetta API offline /construction/parse .

= Code =

Work in progress.

https://github.com/snowblossomcoin/snowblossom/tree/sip4-tx-input-value


= Questions =

= Deployment =

This will be required at block 151680, which will be around 2021.03.25.
At that time mining pools must be running version 1.8.0 or higher.

= Voting =

* Passes when 1000 blocks pass containing 25% voting and &gt;50% agreement
* Pools will represent their miners.
* Set in your miner or pool configuration file either
** <code>vote_yes=4</code>
** <code>vote_no=4</code>

= Sponsors =

* Joseph Gleason - Fireduck (slack) - fireduck64 (github)