phylosignal uses BLAS, which defaults to all cores

[nick-youngblut]

I've been running phylosignal v1.3 on my research group's server, and phyloSignal() uses all cores on our machine by default. I can make enemies by hogging the server. If I use RhpcBLASctl::blas_set_num_threads(), then the number of threads used phyloSignal() is kept in check. So, it appears the phyloSignal will use BLAS (at least on a certain OS config) and default to all threads.

It might be good to include in the docs that RhpcBLASctl::blas_set_num_threads() can be used to prevent all cores from being used.