* Activate `LedgerRef` wrapper for `AccountsCache`
details:
`accounts_cache.nim` methods are indirectly processed by the wrapper
methods from `ledger.nim`.
This works for all sources except `test_state_db.nim` where the source
`accounts_cache.nim` is included (rather than imported) in order to
access objects privy to the very source.
* Provide facility to switch to a preselected `LedgerRef` type
details:
Can be set as suggestion when initialising `CommonRef`
* Update `CoreDb` test suite for better time tracking
details:
+ Allow time logging by pre-defined block intervals
+ Print `CoreDb`/`Ledger`profiling results (if enabled)
* Fix EVM tracer crash bug when serializing nil stack
* Fix t8n tracer doc
add following description to reflect new functionality
`stdout` - into the stdout output.
`stderr` - into the stderr output.
<file> - into the file <file>-<txIndex>.jsonl.
none - output.basedir/trace-<txIndex>-<txhash>.jsonl.