Centrosome

* [Neighbor movement tracking](https://github.com/CellProfiler/centrosome/commit/e1dab16d3483a7820da4fd2cb72a855825b31848) by 0x00b1
* [Upgrade numpy 1.13](https://github.com/CellProfiler/centrosome/pull/75) by oleksandr-pavlyk
* [Faster Zernike polynomials](https://github.com/CellProfiler/centrosome/pull/74) by oleksandr-pavlyk

- Fixed NumPy 1.12.0 compatibility issues

- Fixed NumPy 1.12.0 compatibility issues

- use `skimage.filters.median`

Minor release to support new CellProfiler features:
- Kirsch operator / edge detection filter
- Minor change to zernikes to allow CellProfiler to pass in ijv-style labelings

- included a `skeleton_length` method to compute length of skeletal labels