FEAT: preliminary release of new runtime lexer.red

For now, it is accessible only from the TRANSCODE function.
Currently only block!, integer! and string! parsing implemented.
FEAT: pass-thru for /CASE refinement on PARSE-TRACE.
FEAT: added support to char! parsing to runtime lexer.
FEAT: preliminary code for parsing any-word! and any-path! copied from %lexer.r.
FEAT: added UTF-8 encoder for Red string!
FEAT: lexer now can parse word! and set-word! literals.
FEAT: added support to lexer for get-word and lit-word literals.
FEAT: added support to lexer for issue! and refinement! literals.
FIX: MOLD on path now properly construct path with embedded paren values.
FEAT: added support to lexer for any-path! literals.
FEAT: // can now be loaded as word!.
FEAT: added support to lexer for file! literals.
FIX: added missing hexa bitsets to lexer.
FIX: minor code reduction.
FIX: issue #699 (Parse does not match integer range loop on bitset)
FEAT: added support for hexadecimal literals to lexer.
FEAT: added support for multiline comments to lexer.
FEAT: added support to lexer for simple construction syntax.
FEAT: replaced old ASCII tokenizer by the new Unicode runtime lexer.

- LOAD is now fully defined at mezz level and relies on TRANSCODE function.
- DO temporarily lost his support for string! argument.
FIX: end of multiline strings wrong parsing by runtime lexer.
FEAT: console now switched to Unicode input for Windows platforms (finally!).