Blender Git Loki

Orange; relative path fix for libraries.

- On linking stuff from libraries, each relative path now is relative with
respect to the file that uses the library.

This way you can make libraries that use other libraries, and link them
in your project with an entire different relative path.

The commit also fixes issues when mixing up relative or non-relative paths.

Now after this I need to commit something cool, so the orangers will update
and check! :)