Changelog

Unreleased

Many computations altered to use numpy vectorization over for loop implementations. Including but not limited to:
- 2D sensitivity calculation.
- 1D sensitivity calculation.
- UVW calculation as a function of time.
_utils.find_nearest can solve for the index of an array of inputs.

Added a parameter systematics_mask to PowerSpectrum sensitivity, which enables arbitrary k-modes to be masked out in the sensitivity calculation.
track option to Observation. This is an alias for obs_duration but has a closer resemblance to the original 21cmSense v1.
New calculate_sensitivity_2d_grid method that makes it easier to obtain a gridded cylindrical power spectrum sensitivity for arbitrary bins.

A major overhaul of the code, making it object-oriented and modular.

Python 3 compatibility.
Class-based code, with specific objects for Observatory, Observation, and class templates for different Sensitivity calculations, including default PowerSpectrum.
Clean attrs-based classes.
click-based CLI interface.
Ability to pickle intermediate classes for re-use.
Ability to specify observation frequency more freely (and self-consistently)
Removal of all usage of aipy as it is far too complex for a simple calculation such as this.
Ability to specify Observation using pyuvdata objects.
Useful docstrings throughout.
Explicit cosmological calculations based on astropy.
More flexible: extra parameters for foreground model and integration time, among others.
Agreement with previous versions (not exact agreement, because of the increase in accuracy from using astropy).
Tools for plotting output -- and default 1D PS plot from the CLI.
All quantities have appropriate units (from astropy).
Example documentation, and example configuration files.
Configuration files are no longer python files... they are YAML.