Rank-filter

- Bindings rewritten in Cython (order of magnitude faster than VIGRA bindings).
- VIGRA dependency is now optional.
- Nose no longer required for testing. (using `unittest`)
- Python 3.x support.
- Addition of setup-based build. (used by CMake and hence Conda recipe)
- Made package pip installable.
- Minor CMake fixes.
- Added badges.
- Explained how building now works and what it requires.
- Provide CMake and Conda build option to generate legacy VIGRA Python bindings.
- Convert benchmarks to Python.
- Update Travis CI to test these changes.

- Weird linkage to unneeded library `vigranumpycore.so`.
- Affects CentOS 6.x.
- Seems to be unable to find it on the path.
- Does not actually need to be linked to it.
- Removes linkage using `patchelf` in CMake build.
- Has no effect on non-Linux platforms.
- Has no effect where the linkage is not present (e.g. Ubuntu 12.x).

- Moved repo to [nanshe-org](https://github.com/nanshe-org/rank_filter).
- Converted README to reStructuredText.
- Started using `unittest` in Python for the test suite.
- Switched from VIGRA's testing framework to Boost's testing framework.
- Removed some unnecessary `include`s.
- Added a 1D C++ API for the rank filter that uses iterators and is independent of VIGRA with tests.
- Unpinned the version of `conda-build` used on Travis CI.

- Provides a recipe for building with `conda`.
- Recipe provides `versioneer` style versioning so is PEP440 compatible.
- Allows for the compiler and compiler link arguments to be specified.
- Performs testing as part of the build procedure.
- Provides default values that appear to work on Mac and Linux.
- Dramatically cuts down build time.
- Other minor build fixes.

v0.1.0: Provides the basic rank_filter module for Python based on a C++ implementation. This version has been tested on Mac, CentOS, and Ubuntu. It also passes its Travis CI build.