Protocol 13 Support

[fracek]

This PR reverts back the change that reverted support for m-strkeys, it also enables generating v1 transactions by default.

I think it's a breaking change since it will generate a different type of transaction by default.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• I have read the CONTRIBUTING document.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[coveralls]

Coverage increased (+0.3%) to 85.597% when pulling 4090a9b on protocol-13 into f5f875e on master.

[Kirbyrawr]

Looks ok to me so far.