Fix Mantis 2968: AddressSanitizer: global-buffer-overflow in shield_info_reset() - relates to hud_target_change_check()

git-svn-id: svn://svn.icculus.org/fs2open@10175 387891d4-d844-0410-90c0-e4c51a9137d3
Fix mantis 2967: use Medals array instead of Ranks (from Yarn)

git-svn-id: svn://svn.icculus.org/fs2open@10176 387891d4-d844-0410-90c0-e4c51a9137d3
Added initialization of render box and sphere offsets.

git-svn-id: svn://svn.icculus.org/fs2open@10177 387891d4-d844-0410-90c0-e4c51a9137d3
Fix Coverity 1093549: Negative array index write

(practically impossible to occur, but lets be safe in case multi_voice_get_stream() changes in future)

git-svn-id: svn://svn.icculus.org/fs2open@10178 387891d4-d844-0410-90c0-e4c51a9137d3