Complete OpenMP and Windows compatibility fixes

- Fixed all character encoding issues for Windows MSVC compilation
- Recreated polygon.hpp and polygon.cpp with clean ASCII encoding
- Fixed math library linking for Windows (removed Unix-specific libm)
- Added zlayout.cpp to build configuration (was missing)
- Disabled problematic advanced example targets temporarily
- Updated basic_usage.cpp with English text to avoid encoding issues
- Ensured all tests pass with both --openmp=y and --openmp=n configurations
- Maintained MSVC 2012 compatibility
- All 39 tests pass successfully in both configurations

Author: WenyinWei