(BugId:100980) - Fix inherited categories disappearing when adding new cateogires in view mode.
(BugId:100980) - use category diff to append categories to wikitext.
Normalize method of getting category title across methods. Add return types to functions.
Add test coverage for getCategoryNames.
Alhpabetize
Add test coverage for getCategoryTitle.
Add test coverage for getDiffCategories.
Merge branch 'dev' into bugid-100980
Merge pull request #843 from Wikia/bugid-100980

(BugId:100980) - Fix inherited categories disappearing when adding new cateogires in view mode.