REFACTOR: do not convert operators to lower case

[elrayle]

The original javascript converted incoming operators (e.g. AND) to lower case (e.g. and) during the tokenization process. The initial translation stayed as close to the original javascript as possible and reasonable with assumptions that a later process would require the output to be in the format created in the javascript.

I do not see the need for this case conversion in later processing. Recommending a refactor to not convert operators case.

[elrayle]

Is there an advantage to requiring a specific case? Consider making the parser case-insensitive for operators.