Clean up Multiple-selection list Tunables a bit

Change-Id: I28eef2218cde0bfa80755bb88ec7a92196c60652

Conflicts:
	work-swing-impl/impl/src/main/java/org/cytoscape/work/internal/tunables/ListMultipleHandler.java
Merge branch 'develop' of git+ssh://github.com/cytoscape/cytoscape-impl into develop