Better docs, conda based install.

- Enable numpydoc extension
- Use ReadTheDocs theme,
- Add docs sections: Install and devel
- Conda based build (bug fixed conda-build 1.9 upstream )
- better setup.py
- Rel. import in __init__.py
- Make travis build inplace (py.test tests local tree)
- Use python library from conda environment for distutils based local build.
- Fix Py3 issue: reduce -> functools.reduce
- Update .travis.yml
Better CI builds. [release]

- Use conda build --output to get path of binary blob in travis
- Update .drone.yml
Merge pull request #1 from bjodah/enhance_docs

Enhance docs