WIP: Fix for wind direction binning

Small fixes in `tinylib` to:

1. Shift boundaries for wind direction binning such that unpacked centered wind dirs coincide with 2nd order cardinal directions rather than sitting between them.

2. Handle wrap-around at -180 degrees for wind direction binning 

Work in progress, needs more clean-up and testing
added `atol` because test will otherwise fail for 0-like wind speeds with e.g. actual=1e-7 and desired=1e-20.