Memory allocation

[Fredrik Roos]

According to the guidelines in the ox-api docs, memory
allocation is not allowed during ox_work(). But if you
need temporary buffers during processing, this is the
only place where the blocksize is known. With the 
current API, you have to allocate memory in ox_work().
What about a callback similar to ox_update() that tells
the plugin when the host want to change the blocksize?

    --fredrik