Due to compatibility concerns, this is temporarily disabled.

Also rename method to better match what it does.

This enables srp.

Before this commit autofast for Android was ignored if the user was sneaking, digging or building. There is no reason for this and it impedes movement control

Also optimize json's library

Adds everything needed for SRP (and everything works too),
but still deactivated, as protocol v25 init packets aren't final yet.
Can be activated by changing the LATEST_PROTOCOL_VERSION header to 25
inside networkprotocol.h.

Uses system provided libgmp if found, if not it falls back to mini-gmp.

Now matches function comment

Improve schematic file-saving interface
Add ability to create temporary test files

Fixes #2678

This simplifies NodeResolver logic and makes some interfaces cleaner.