Add support for protocol 14

[fracek]

This PR implements all the changes required for Protocol 14 (#274).

Types of changes

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

[coveralls]

Coverage increased (+3.1%) to 88.68% when pulling f5c851770aad520c228a9c78ba4fe7162d2b7a93 on protocol-14 into a73d03c16ccd1301b566a1a298b53cc66582e231 on master.