The run loop, which previously contained custom opcode executes have been
removed and has been simplified to a few checks.
Each operation consists of 4 elements: execution function, gas cost function,
stack validation function and memory size function. The execution function
implements the operation's runtime behaviour, the gas cost function implements
the operation gas costs function and greatly depends on the memory and stack,
the stack validation function validates the stack and makes sure that enough
items can be popped off and pushed on and the memory size function calculates
the memory required for the operation and returns it.
This commit also allows the EVM to go unmetered. This is helpful for offline
operations such as contract calls.
Environment is now a struct (not an interface). This
reduces a lot of tech-debt throughout the codebase where a virtual
machine environment had to be implemented in order to test or run it.
The new environment is suitable to be used en the json tests, core
consensus and light client.
that specifies the maximum number of elements in the `structLogs`
output. This option is useful for debugging a transaction that
involves a large number of repetition.
For example,
```
debug.traceTransaction(tx, {disableStorage: true, limit: 2})
```
shows at most the first two steps in the `structLogs`.
* change gas cost for contract creating txs
* invalidate signature with s value greater than secp256k1 N / 2
* OOG contract creation if not enough gas to store code
* new difficulty adjustment algorithm
* new DELEGATECALL op code
* Add params package with exported variables generated from
github.com/ethereum/common/blob/master/params.json
* Use params package variables in applicable places
* Add check for minimum gas limit in validation of block's gas limit
* Remove common/params.json from go-ethereum to avoid
outdated version of it
