Phoebe

* fix bug where flipping Kepler's third law constraint multiple times would fail.
* fix bug when flipping requivsumfrac and requivratio constraints.

* fix typo that raised error when using use_server with features attached
* added new `addl_slurm_kwargs` parameter to pass any options to slurm scheduler

* fix conversion between l3 and l3_frac to account for distance when pblum_mode is absolute
* fix tagged phoebe version in cached bundles to avoid import warning

* fix filtering error when not explicitly passing solver to run_solver
* fix exposing analytic model from lc geometry estimator
* fix phase-sorting when plotting solution from ebai estimator

* add support for differential evolution optimizer solver
* add support for differential corrections optimizer solver
* optimizers: ability to continue runs from previous solutions (for most optimizers)
* improvements to geometry and ebai estimators to use ligeor as a new built-in dependency
* gaussian processes now use celerite2 or scikit-learn instead of celerite
* emcee sampler: additional plotting styles to check for convergence, checks to ensure starting sample is physical, and added ability to continue a previous run from any arbitrary iteration in a previous run
* new support for running jobs on external servers via crimpl
* clarified distinction between chi2 and mle

* fix bug where creating a custom constraint for parameters within features was not correctly identifying the constrained parameter and was raising an error when attempting to set the value of the constraining parameter.