1. Use cinvoke macro instead of invoke for con_printf
2. Convert `end:` to `P_END:`, As the previous one was a FASM keyword
3. Upgrade all functions in libunicode.asm to use stdcall convention
- Added libunicode.asm to parse UTF-8 strings.
- Implemented count_utf8_codepoints to skip continuation bytes.
- Implemented count_utf8_graphemes to handle ZWJ (E2 80 8D) and combining marks (CC/CD).
- Added console.asm to the examples folder to test and print the results.
- Submitted for GSoC qualification task.