* 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)
simplify EVM and delegete those things to accounts cache.
also no more manual state clearing, accounts cache will be
responsible for both collecting touched account and perform
state clearing.
Jordan Hrycaj
jangko