Fixed building on OSX 10.5 and newer
Added documentation for OSX Build fixes
Make import of Joint node hierarchies less strict
Revert "Make import of Joint node hierarchies less strict"

This reverts commit e2e8ec7c0eb18a40ebccd1fed856cea6da758a93.
Merge pull request #220 from gaiaclary/master

Fixed building on OSX 10.5 and newer