This converts the internal mining package to use the stdaddr package
instead of dcrutil.Address as well as to support script versions.
All callers that use the mining package in the repository are updated
accordingly to maintain code that continues to build and work properly
as well as pass all tests. In order to achieve this, it introduces
temporary address conversion code that will be removed in future
commits.
This is part of a series of commits to convert all packages in the
repository to make use of the new stdaddr package.
12d7c2d44f
