Remove old whispersystems, etc. *25519 and use new v1.61 BouncyCastle.
Fix proxy forging private key derivation from X25519 shared secret.
Also include Javascript test version for comparison.
Fix block rewards for proxy forging.
Add extra useful info to API call GET /admin/forgingaccounts.
Fix API response to POST/DELETE /admin/forgingaccounts when
passed invalid private keys.
Added block rewards and account flags to testchain config.
Tests to cover changes above.
