bytes and xstrings handled incorrectly

[wesnm]

There is an issue in get_byte_value and (I believe) get_xstring_value. The buffer is treated as a SAP_UC when it should be as a vector of raw bytes or a raw string. The attached patch allows invoking a method that returns a table with a byte value succeed where it previously failed with "embedded nul". I haven't run across an xstring but I believe it could fail in a similar manner. Sorry I'm not familiar enough with git to do this as a pull request!

patch.txt

[piersharding]

Hi @morganw3 - thanks for this, I have applied the patch and pushed version 0.11. Could you please test, and let me know.

Thanks, Piers.

[wesnm]

Looks great, thanks!