Add support for more kinds of redirect operators in Eshell
* lisp/eshell/esh-arg.el: Require cl-lib.
(eshell-finish-arg): Allow passing multiple ARGUMENTS.
(eshell-quote-argument): Handle the case when 'eshell-finish-arg' was
passed multiple arguments.
* lisp/eshell/esh-cmd.el (eshell-do-pipelines)
(eshell-do-pipelines-synchronously): Only set stdout output handle.
* lisp/eshell/esh-io.el (eshell-redirection-operators-alist): New
constant.
(eshell-io-initialize): Prefer sharp quotes for functions.
(eshell-parse-redirection, eshell-strip-redirections): Add support for
more redirection forms.
(eshell-copy-output-handle, eshell-set-all-output-handles): New
functions.
* test/lisp/eshell/esh-io-tests.el
(esh-io-test/redirect-all/overwrite, esh-io-test/redirect-all/append)
(esh-io-test/redirect-all/insert, esh-io-test/redirect-copy)
(esh-io-test/redirect-copy-first, esh-io-test/redirect-pipe): New
tests.
* doc/misc/eshell.texi (Redirection): Document new redirection syntax.
(Pipelines): Document '|&' syntax.
(Bugs and ideas): Update item about redirection syntax.