Added folder with solidity 0.5.0 compatible validator set contracts

[Genysys]

Fixed breaking changes to validator set contracts. Left old folder as most people are still on 0.4.*

[coveralls]

Pull Request Test Coverage Report for Build 96

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 91:	0.0%
Covered Lines:	77
Relevant Lines:	77

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💛 - Coveralls

[andresilva]

Thanks for the PR! 👍 Instead of creating a new folder what do you think about us creating a solidity-0.5.0 branch for this. It would be easier to diff the changes and it would also allow us to update truffle to the latest version which I think uses Solidity v0.5.0, this will make sure that the whole test suite is run against the updated contracts in this PR. We could also add a note in the README (of the master branch) pointing to the branch that supports Solidity v0.5.0.

[Genysys]

Sounds good happy to make those changes @andresilva