Refactor TransitiveLookupWriter for multi-threaded use
Merge branch 'mbst-6785-multi-equiv-write' into stage

* mbst-6785-multi-equiv-write:
  Refactor TransitiveLookupWriter for multi-threaded use

Conflicts:
	src/main/java/org/atlasapi/persistence/lookup/LookupWriter.java
	src/main/java/org/atlasapi/persistence/lookup/TransitiveLookupWriter.java