Implement multi-threaded async file and socket operations with pthread-based worker pool, add double floating-point type with conversion and arithmetic functions, introduce file I/O system with fopen/fclose/fread/fwrite/fgets/fputs, and add break/continue control flow statements. Update Makefile with new test and example targets, extend README and TUTORIAL.md with comprehensive documentation and usage examples, and include async_demo.rc example and async_io_test.rc test suite.
Implement prefix and postfix ++/-- operators in the tokenizer (Inc/Dec token types) and parser (factor/unary functions) with correct pre/post semantics. Add increment_decrement_test.rc covering all four operator forms. Update Makefile to include the new test file in TESTS, add run-increment-decrement-test target, and fix .PHONY and TARGET dependency on dirs.
