First attempt at implementing an option for the parser to support case
insensitive keywords (e.g., "program", "PROGRAM", "Program" ... in
PL/0).
Implemented new option caseInsensitiveKeywords to advise the parser to
accept keywords in any case constellation (e.g., "program", "PROGRAM",
"Program" etc. in Pascal).
Merge branch 'master' into caseinsensitivekeywords