- Removed WMM coefficient files and URLs.
- Adding note to README re: WMM output as predictions and referenced IGRF.

- Updated Gauss coefficients for WMM2020.
- Significantly improved numerical stability by using closed-form equation for associated Legendre polynomials, instead of recursion.
- Improved speed by ~7x by using multidimensional arrays.
- Per WMM2020, this version now displays a blackout zone warning when the horizontal intensity is below 6000 nT.
- In addition to orthogonal magnetic field components,
`GetMagneticFieldWMM`

returns the magnetic field elements*h*,*f*,*i*, &*d*as well as their secular variation.

First release of wmm package. Contains 1 exported function,
`GetMagneticFieldWMM`

, which calculates magnetic field.