make init_ship_entry actually init all the fields in ship_info
make draw_weapon_models a ship flag instead of a boolean
remove the MAX_SHIP_FLAGS #define because it didn't mean what everybody thought it meant

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@10127 387891d4-d844-0410-90c0-e4c51a9137d3