Updated libnix available in MDC files section.

In the file section you can now download an update for libnix (the update will also attempt to correct some other issues with the SDK, so it's worth installing for everyone with the SDK), just unarchive and run the included updatesdk script.    

Here's a rough draft of some of (but not limited to) the things that changed:

• Lots and lots of new functions, most notably new *fast* (including C99 float variants) math functions.
• More bugfixes than you can shake a stick at. Also optimized bcopy/zero/memset functions.
• Overhauled I/O system, safer to use multithreaded now (but remember, not all function are *meant* to be!).
• De/constructor improvements, will f.ex. not link if they are not handled (ie, not linked against startup.o).
• Functions that don't strictly need I/O no longer depend on it (ie, sprintf&co are safe in libraries now).
• The print/scanf family of functions now support 64bit (%ll) in/output.

NOTE: Destructors created using constructor.h *must* be recompiled to function correctly!