Thirty four crates listed apsis-core or apsis-math without referencing it,
and apsis-kepler listed apsis-time and apsis-tle as well. Each was verified
removable by compiling with it taken out. An unused dependency still costs
build time and makes the dependency graph and the layer check report
relations that do not exist. The layer check now reports 104 edges, down
from 141.
ApsisRS contributors