mjucker/aostools: aostools v2.1.5

A few bugfixes, and extended functionality:

• GetWaves() and ComputeEPDiv() can now receive a list of wave numbers
• ComputeAnnularMode() now deals with both hemispheres - either explicitly with hemi or implicitly by looking at the sign of latitude inputs
• eof() can now be calculated based on removing the mean (detrend='constant') or a linear trend (detrend='linear').