In addtion to already supported LIMIT/OFFSET variants allow more to be parsed
Legacy:
- LIMIT int
- LIMIT int OFFSET int
Enhancement:
- OFFSET int (no limit)
- LIMIT ALL (no limit)
- LIMIT NULL (no limit)
- LIMIT ALL OFFSET int (no limit, but offset)
- LIMIT NULL OFFSET int (no limit, but offset)
Also ensures negative limits / offsets are set to kNoLimit/kNoOffset