Basic implementation without tests for findAllRefs/getOccs for 'super' keywords.
Added tests for getOccurrences on super.
Disabled findAllRefs for 'this'/'super'.
Separated 'super'/'this' keyword searching to simplify logic.
Addressed CR feedback.
Merge pull request #632 from Microsoft/getOccurrencesSuperThanksForAsking

Get occurrences for 'super' keywords