Blender Git Loki

Part 2 of 64 bits fixing; the files.

The good news; previously written 64 bits are still valid! All fixes
appeared to be possible in code, no versioning patches needed. :)
That also removes the I AM STUPID 64 bits ban from the code.

The bad news:
I couldn't get a 64 bits Blender running here (ghost-mac issues... it
has to be recoded using Quartz to be able to run 64 bits). So what I
have tested was:

32 bits binary:
- Appending/linking data from 64 bits file.
- Reading 64 bits chained library-linked files (file -> file -> etc)
- Linking 32 bits files with 64 bits files

This has to be tested for 64 bits too. Will drop in IRC now to help.