Add additional namespaced/tagged API functions to access same function using either specific types or co_obj

[jheretic]

We currently do a bunch of conversion, especially for functions taking string arguments, between co_strings and cstrings, depending on what that particular function demands. Where it makes sense, we should add throughout multiple declarations of a particular function with clear namespace tagging (for instance, either an _obj tag or a _cstr tag at the end, but probably not both) in order to accommodate both types of strings without a lot of switching back and forth.