Changes summary:
- Continue with the gasLimit check skip in ``verifyHeader`` of
``merge.go`` for unless pre-merge block and blockGasLimitContract
present
- Refactor ``aura.go`` a bit
- Have ``sysCall`` method customized to be able to call state (contract)
at a parent (or any other) header state
* handle chain flag in integration
* handle chain flag in integration
* handle chain flag in integration
* save
* save
* merge devel
* save
* noopWriter - one is enough
* chain spec parser
* chain spec parser
* embed
* embed
* embed
* embed
* embed
* embed
* embed
* clean
* clean
* correct alloc after reset state
* correct alloc after reset state
* correct alloc after reset state
* integration reset state now does re-apply genesis and chainConfig
* eips summary
* eips summary
* eips summary
