dot-clean_chain: Tidy C++ outputs before writing to disk.
In BayesSpace: Clustering and Resolution Enhancement of Spatial Transcriptomes

1) Convert each parameter to matrix (n_iterations x n_indices) 2) Add appropriate colnames 3) Thin evenly (for enhance)

1	.clean_chain(out, method = c("cluster", "enhance"), thin = 100)

`out`	List returned by `cluster()` or `deconvolve()`.
`method`	Whether the output came from clustering or enhancement. (Different params are included in each.)
`thin`	Thinning rate. Some enhanced parameters are thinned within C++ loop, others (`mu` and `Ychange`) need to be thinned afterwards.