support byRef in builtin functions
support builtin variables get and set
use OverrideBuiltinVariable() in special scopes
add char->Token map to lexers
add support for some comparison operators

Parse >, <, >=, <= (and >>, >>=, <<, <<=) and add infrastructure
for ET generation of comparison operators. Add first version of
ET generation, without type matching.
fix b0b84617e1ae3f: must expose punctuation map
add operation type to BinaryOperator

Replace old IsArithmetic(), IsComparison() methods
and use in IsCompoundAssignment().