Re: Dynamic loading progress

[Aurélien Aptel]

I've added user-pointer objects. Some feedback I had off-list:

* add functions to the API for fast vector access as it currently
requires too much boxing/unboxing of integers for doing
length/indexing stuff.
* expose fast read-only string access (not sure how do-able this is
considering the encoding problem)
* consider NULL as a no-op finalizer.

Philip, you obviously have more experienced in this memory handling
stuff so I'm going to trust you and merge what you did (but there are
merge conflicts on the last pull requests atm, havent looked into it).
Thanks again for your work :)

This module API is slowly but surely materializing. The interface is
lot more clean and user-friendly than my initial plan. I hope we can
have good performances where it matters to make it really useful :)