* Difficulty Contextual RFC: Introduction
Add a header, summary, and motivation
* Difficulty RFC: Add draft definitions
And update the state RFC definitions to match.
* Difficulty RFC: Add relevant chain
* Difficulty RFC: draft guide-level explanation
Outline the core calculations and checks.
* Difficulty RFC: Revised based on spec fixes
Update the design based on the spec bugs in #1276, #1277, and
zcash/zips#416.
These changes make the difficulty filter into a context-free check,
so we remove it from this contextual validation RFC.
* Difficulty RFC: Explain how Zebra's calculations can match the spec
* Difficulty RFC: write most of the reference section
Includes most of the implementation, modules for each function, and
draft notes for some of the remaining parts of the RFC.
* Difficulty RFC: Add an AdjustedDifficulty struct
* Difficulty RFC: Summarise module structure in the one place
* Difficulty RFC: Create implementation notes subsections
* Difficulty RFC: add consensus critical order of operations
* Difficulty RFC: Use the ValidateContextError type
* Difficulty RFC: make the median_time arg mut owned
We have to clone the data to pass a fixed-length array to a function,
so we might as well sort that array to find the median, and avoid a
copy.
fc7d37c984