Remove unnecessary method Utils.replace (already exists as String.replace)
Pair and Triple are immutable, and Triple is not a Pair
Add a non-null default source Pair for CommonToken
Clarify type widening casts
Simplify LEXER_CHAR_SET rule
Do not allow raw newline characters in a lexer char set
Do not allow raw newline characters in lexer string literals
add TODOs and fix a -1 to be a constant.