the bulk of the changes to get rid of fd_ptr and move print open

the bulk of the changes to get rid of fd_ptr and move print open
handling to printing/printing.c

most of this was just replacing things like fsp->fd_ptr->fd with fsp->fd

the changes in open.c are quite dramatic. Most of it is removing all
the functions that handled the fd multiplexing
(This used to be commit d1827a3648009fd0a0d165055015d9aeda7a1037)