Hotfix for startup crashes on Oculus runtime and imports failing due to defining an invalid thumb bone segment! Compatible with previous, don't need to update unless you're running into issues.

Bugfixes:

- Fixed import failing on rigs that have a thumb bone labeled as intermediate segment (reported by @かず (kazu / GitHub: kazu0617))
-- Real thumbs do not have intermediate segment, only metacarpal, proximal and distal. When it's defined as intermediate it's assumed to be distal instead.
- Fixed crash on startup when using the Oculus runtime (reported by @Zandario and @Froppy)