[PATCH] make )savesystem work with frames

[Qian Yun]

I've revived the ")savesystem" command to make it
work properly with frames.

I've tested it with sbcl/clisp/ccl/gcl on linux and
sbcl on windows.

It works with hyperdoc and graphics. I think this
would be a handy feature and so far I've found no
additional issues. I welcome you to give this a
test and report any issues to me.

- Qian

You can test it like this:

$ fricas ## you can run with -nosman as well, both works

(1) -> x := 1

(1) 1

(2) -> )savesystem save1

$ fricas -ws ./save1

openServer result 0

(2) -> x

(2) 1