Rank-filter

- Requires C-contiguous arrays as input to `lineRankOrderFilter1D_floating`.
- When swapping axes initially in `lineRankOrderFilter` ensure the array is contiguous instead of copying.
- During second swapping of axes in `lineRankOrderFilter`, don't make a copy of the intermediate just copy from the view. (this is faster)
- If the input and output arrays are the same array, don't copy data over. (doesn't check views)

- Works around a race condition between the build and test step on Mac using Python 3.5.

- Make sure the library `rank_filter` is cleaned up even if it has some suffix before the `.so` extension.

- Swap the NumPy/Python order in the build string to match other packages.

- Add workaround in `setup.py` to not install setup requirements when using non-build commands. (e.g. checking help)
- Correct code markup in the README.
- Add a few more classifiers to the package.
- Fix benchmarking on Travis CI to use the current version.
- Note the license in `setup.py`.
- Have git ignore some build and editor files.
- Fix up CMake Python testing a bit.

- Fix rendering of installation code in README.
- Add some more trove classifiers.