Allow any returns in native callbacks

[Headline]

Native callbacks currently require plugin authors to retag their returns to an int, but by adding any as another acceptable prototype we allow them to return without needing to retag.

public any Native_Something(Handle plugin, int numParams)
{
    float val =5.0;
    return val; // no tag mismatch
}

Thanks asherkin for bringing this change to light

[KyleSanderson]

I guess we still need int in there for old code? is this correct?

[Headline]

The typeset has the older int prototype, this shouldn’t break anything older. Many of our built-in plugins still use the int counterpart and they compile

[KyleSanderson]

Why not just change it to any then? Does this give some micro-optimization?

[Headline]

@KyleSanderson if we changed int to any and kept the typedef, then every callback would have to be rewritten. While int, float, char can coherse to any, they're still different types and the compiler errors out w/ prototype mismatch. We need that typeset(funcenum) for this change to be possible.