fix for mantis 2874: Pilot conversion not preserving axis mappings. Also adds a warning that is activated whenever the pilot loading process has to skip bytes of "extra/unknown data" in a section.

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@9748 387891d4-d844-0410-90c0-e4c51a9137d3