SHTOOLS: Version 3.4

This release adds missing functionality to the SHGrids, SHCoeffs, and SHWindow classes, and adds support for PyPI. Add pyshtools to PyPI repository. Can now be installed using pip install pyshtools. Add new function SHBiasKMask which is the arbitrary window counterpart to the spherical cap window SHBiasK. Add get_biasedpowerspectrum() method to SHWindows for arbitrary windows. Add copy() method to all classes, which returns a deep copy of the instance. Add __sub__, __add__, __rsub__, __radd__, __mul__, __div__, __truediv__, and __pow__ operators for two sets of coefficient or grid classes, or one coefficient or grid class and a scalar. Add nwinrot option when rotating spherical cap windows in SHWindow that will rotate only the first nwinrot windows. Add degrees option to get_lats() and get_lons() methods. Add the constructor from_file() to initialize an SHGrid with a numpy formatted data file. Add option to read coeffs and grids from a numpy formatted binary file. Addtofile() methods to output raw grid and coefficient data as either text or binary formatted files. Update Intro 1 notebook and add example to Intro notebook 2 showing how to use arbitrary localization windows. Convert notebooks to html and add links to web documentation. Add option fixed_power to SHCoeffs.from_random() method to generate random coefficients that fit exactly the expected power spectrum. Add Earth topography coefficients referenced to mean sea level to the example files, expanded to degree 300: srtmp300.msl