message: add LedgerParameters in the Leadership object
diff: use crate::{
  block::{AnyBlockVersion, BlockDate, BlockVersion, ConsensusVersion, Header},
  date::Epoch,
  - ledger::Ledger,
  + ledger::{Ledger, LedgerParameters},
  stake::StakePoolId,
  };
  use chain_crypto::{Curve25519_2HashDH, Ed25519Extended, SecretKey, SumEd25519_12};
  @@ -75,6 +75,7 @@ pub struct Leadership {
  epoch: Epoch,
  era: TimeEra,
  inner: LeadershipConsensus,
  + ledger_parameters: LedgerParameters,
  }
  impl LeadershipConsensus {
  @@ -142,6 +143,7 @@ impl Leadership {
  epoch: epoch,
  era: ledger.settings.era.clone(),
  inner,
  + ledger_parameters: ledger.get_ledger_parameters(),
  }
  }
  @@ -157,6 +159,12 @@ impl Leadership {
  &self.era
  }
  + /// access the ledger parameter for the current leadership
  + #[inline]
  + pub fn ledger_parameters(&self) -> &LedgerParameters {
  + &self.ledger_parameters
  + }
  +
  /// Verify whether this header has been produced by a leader that fits with the leadership
  ///
  pub fn verify(&self, block_header: &Header) -> Verification {
  