Build and test core
Build and test core

Let's see if this works as a CI.
mrjbq7/factor,mrjbq7/factor,tgunr/factor,tgunr/factor,mrjbq7/factor,tgunr/factor,tgunr/factor,mrjbq7/factor,mrjbq7/factor,factor/factor,factor/factor,factor/factor,mrjbq7/factor,tgunr/factor,factor/factor,factor/factor,tgunr/factor,factor/factor