[Csv] bug fixed

[Skip Montanaro]

I should have paid closer attention to the errors malloc was giving me:

    *** malloc[1859]: Deallocation of a pointer not malloced: 0x4aa5e8; This
        could be a double free(), or free() called with the middle of an
        allocated block; Try setting environment variable MallocHelp to see
        tools to help debug

especially the bit about "free() called with the middle of an allocated
block".  Memory allocated with PyMem_Malloc() was being freed with free().
Since Python now uses its own custom allocator layered on top of malloc,
those calls really need to be balanced.  I've no idea what free() on the
platforms you were using was doing (maybe ignoring, maybe scribbling), but
thankfully free() on my Mac OS X machine complained.

Please "cvs up".

BTW, the Object Craft csv module has the same problem.  Time to release 1.1?
;-)

Cheers,

Skip