Improvement to the Test Framework in the processing of test blocks

We've coded and tested changes to the Bitcoin testing framework to allow the creation and processing of blocks in unit test cases in order to test ProcessBlock(), CheckBlock(), ActivateBestChain(), ActivateBestChainStep() and ConnectTip(), including block-chain reorganizations, majority rules, block version changes and more. Several new test cases were added to enrich the test suite.

Please review and comment the pull request:

https://github.com/bitcoin/bitcoin/pull/4688

Best regards, Sergio Demian Lerner & Timo Hanke