Added asilib.Imagers

[0.18.0] - 2023-07-22

Added

• asilib.Imagers() class to make mosaics and synchronize plotting multiple imagers. The first two methods implemented are:
  • asilib.Imagers.plot_fisheye() to plot fisheye lens images from multiple imagers, and
  • asilib.Imagers.plot_map() to project images from multiple imagers onto a map. This method has an overlap kwarg that by default masks out the (lat, lon) skymaps that map to pixels that overlap with a neighboring imager. This is a surprisingly efficient method that needs to be run just once (tested for up to five imagers; I'm unsure how a 10 or a 20 imager array will fare).
• Added plot tests for the two Imagers methods.
• Added an Imagers() description in the Get Started and API pages.

Changed

• Refactored the Donovan+2008 auroral arc example to use asilib.Imagers.plot_map().
• Added a check to allow custom matplotlib.colors.Normalization object to be passed for color_norm.