Cross-validation methods for LDATS

This is a package to extend and improve the performance of LDATS when applied to short, high-dimensional timeseries (such as the Breeding Bird Survey). Specifically, it includes functions to implement model selection via leave-one-out crossvalidation, and summary functions for examining the number, timing, and magnitude of community reorganization events. The functions are designed to work with data obtained via the MATSS package and to run at scale using drake or similar pipeline managers.