solidity 0.5: issue w/ address datatype payable

[mattiaerre]

as per @maxsam4 comment on Gitter:

one thing about solidity 0.5. Address datatype can now be address payable. prettier cannot handle that.

[mattiaerre]

example:

pragma solidity ^0.5.0;

contract demo {
    function hello() public view returns(bool,bool) {}
}

contract demo2 {
    function world(address payable _yo) public view {
        bool yo;
        (yo, ) = demo(_yo).hello();
    }
}

[mattiaerre]

fixed by #77