This combines two enhancements to the ledger_data RPC
command and related commands.
The ledger_data RPC command will now return the ledger header
in the first query (the one with no marker specified).
Also, ledger_data and related commands will now provide the
ledger header in binary if binary output is specified.
Modified existing ledgerdata unit test to cover new functionality.
When started with "--start", put all known, non-vetoed
amendments in the genesis ledger. This avoids the need
to wait 256 ledgers before amendments are enabled when
testing with a fresh ledger.
Replace Journal public data members with member function accessors
in order to make Journal lighter weight. The change makes a
Journal cheaper to pass by value.
Also add missing stream checks (e.g., calls to JLOG) to avoid
text processing that ultimately will not be stored in the log.
