EIPs 155, 160, 161 (#2976)

* The front-end for each hard-fork, also EIP-160.

* Address EIP161 a/c

* Include EIP-161b

* EIP-161 part d.

* Fix test build.

* Fix one test, add another.

* Fix use of bloom & renaming.

* Initial groundwork for EIP-155

* Fix minor bug.

* Fix all tests finally.

* Rest of EIP-155.

* Add tests for EIP-155 algorithm.

Update transaction tests validation.

* Minor reformat.

* Address grumbles.

* Remove unused code.

* Fix SUICIDE gas mechanism and add consensus tests.

* Remove commented code.

* Set Frontier hardfork block number

* Fix warning.

* Transaction tests,