Update to latest libriscv with new guest datatypes

Use the local cache when a callsite is unknown

Update libriscv with more accurate best-effort symbol lookup

Update README

Fix C++ API compiler flags for C sources

Make failing loading/compiling binary translations into warnings

Try using argument type directly for class_name for public API

Allow up to 11 unboxed arguments, relaxing max 7 args rule

The arguments are correctly spread over integral and FP registers, and a final check is done at the end to verify limits

Remove elf_hint argument to get_hotspots() and make total first argument

Add more Node methods and improve existing ones