hilbert 0.2.1

• Added simple vignette for understanding the encoding process.
• Added return value documentation for core functions.

hilbert 0.2.0

• Added 64-bit integer support for index, position, coords_to_position, and position_to_coords. If these functions are called with n >= 16L, then bit64::integer64 is used in place of base::integer types.
• Added more unit tests for R functions.
• Added cpp11 to LinkingTo field instead of vendoring.

hilbert 0.1.0

• Added a NEWS.md file to track changes to the package.
• Inital version bump to 0.1.0.