After thinking about it, we should remover the bf_releasebuffer checks
when using the old typecodes '#' (the doc should also clearly state that
these are unsafe and '*' is preferred).

If a type chooses to implement the /old/ buffer API and if a method
requires the /old/ buffer API instead of the new one (that is, by using
a '#' typecode), we have to accept these choices.

Here's a patch for trunk, combining the new buffer API for `array` and
the checks removal in getargs.c.