Istanbul Draft EIP-1108 Support

[holgerd77]

Addresses #539.

WIP, first push to run the tests against ethereumjs-common v1.2.1.

I think for the time of Istanbul development we should fix the common dependency version (have done this here) to have more predictable Istanbul behavior since EIPs might change and we don't want to do major version bump for every change here over on the Common side.

[coveralls]

Coverage remained the same at 94.997% when pulling adcfc76 on istanbul-draft-eip1108-support into 5d4fa87 on master.

[holgerd77]

Ok, this is now ready for review. I've added some API tests for the precompiles touched in a separate istanbul/ folder, this can serve as some directory structure also for other EIP tests.

I also added these tests as regular precompile tests running against Petersburg within the normal test directory structure, should be helpful also for further precompile testing and development.

[s1na]

Those tests look great, thanks Holger 😄

[holgerd77]

Thanks, I can really need some kind words the few times I'm doing something directly productive! 😋