Ports FBX module from 3.2 branch to 4.0
This is the only time the plugin will be updated from 3.2 and marks the final time we do this, from now on we will backport FBX to 3.2 with fixes.
Changelog:
- fixed crash importing files with buggy format (because of bad newlines in ASCII data, this is yet to be fixed fully)
- fixed const correctness with C++/C version change
- rewrote material handling to be simpler and better
- ports from 3.2 to 4.0 the fbx importer
