Minor API Release

The changes in the API in this release are really minor. We had to bump minor version of the API because we've added another constant to the StructureError enum. This is literally all changes - if you have your code working under API 6.0.x or 7.0.x, it will surely work with 6.1.x and 7.1.x, respectively.

See Structure API Versions for full version information and downloads.