* lisp/eshell/em-unix.el: Moved su and sudo to...
* lisp/eshell/em-tramp.el: ...Eshell tramp module
* doc/misc/eshell.texi: Updated manual to reflect changes.
External su and sudo commands are now the default; the internal,
TRAMP-using variants can still be used by enabling the eshell-tramp
module.