ssec/sift: Version 2.0.0b0

Much of the work for this version was done by a private contractor in a non-GitHub git service. As such, the normal GitHub issue/PR-based changelog is not available. Below is a summary of the changes. reading of data from both geostationary (GEO) as well as low-Earth-orbit (LEO) satellite instruments visualization of point data (e.g. lightning) support for composite (RGB) visualization an improved timeline manager integration of a statistics module full resampling functionalities using Pyresample an automatic update/monitoring mode partial redesign of the UI/UX ... many more small but useful features