AbstractExtractDependenciesCollector

Extract the dependency information of a compilation unit.

To understand why we track the used names see the section "Name hashing algorithm" in http://www.scala-sbt.org/0.13/docs/Understanding-Recompilation.html To understand why we need to track dependencies introduced by inheritance specially, see the subsection "Dependencies introduced by member reference and inheritance" in the "Name hashing algorithm" section.