* Add header comments

* Add header comments on 3 more contracts

* Add todo tag to all complete contracts

* Update contracts/optimistic-ethereum/OVM/execution/OVM_SafetyChecker.sol
Co-authored-by: ben-chain <ben@pseudonym.party>

* Update contracts/optimistic-ethereum/OVM/execution/OVM_SafetyChecker.sol
Co-authored-by: ben-chain <ben@pseudonym.party>

* Update contracts/optimistic-ethereum/OVM/execution/OVM_SafetyChecker.sol
Co-authored-by: ben-chain <ben@pseudonym.party>

* save notes

* save

* Add last of the header comments

* Update contracts/optimistic-ethereum/OVM/bridge/OVM_L1CrossDomainMessenger.sol
Co-authored-by: ben-chain <ben@pseudonym.party>

* Update contracts/optimistic-ethereum/OVM/bridge/OVM_L2CrossDomainMessenger.sol
Co-authored-by: ben-chain <ben@pseudonym.party>

* Update contracts/optimistic-ethereum/OVM/execution/OVM_ExecutionManager.sol
Co-authored-by: ben-chain <ben@pseudonym.party>

* Update contracts/optimistic-ethereum/OVM/precompiles/OVM_L1MessageSender.sol
Co-authored-by: ben-chain <ben@pseudonym.party>

* remove Execution Env field from headers

* Clarify comment

* Improve comments on Lib_SafeExecutionManagerWrapper

* Update contracts/optimistic-ethereum/OVM/execution/OVM_ExecutionManager.sol

* Update contracts/optimistic-ethereum/OVM/execution/OVM_ExecutionManager.sol

* Update contracts/optimistic-ethereum/OVM/execution/OVM_StateManager.sol

* Update contracts/optimistic-ethereum/OVM/execution/OVM_StateManager.sol

* Update contracts/optimistic-ethereum/OVM/precompiles/OVM_ProxySequencerEntrypoint.sol

* Update contracts/optimistic-ethereum/OVM/verification/OVM_StateTransitioner.sol
Co-authored-by: ben-chain <ben@pseudonym.party>