Corrected names violating the reserved double-underscore.
Added cc_unique_ptr class and test; updated test/general/headers.
string: corrected compiler checks for DUCT_STR_U8, use _ prefix for param.
config: added DUCT_STRINGIFY().
Added Gnarly Report sub library.¹

1: This was yanked from Hord. GR is not for the faint of heart.
config: removed quotation marks from #error directives.