New system released

[MOON at MIT-AI (David A. Moon)]

System 53.15, with microcode 707 and Zmail 8.5, is now released to users.
It should get distributed to all the Tech Square Lisp machines within a day
or two.

The principal change from system 51 is pathnames.  The file name processing
stuff has been completely done over and is now cleaner and easier to use.
If you use anything in the FS: package, you may notice the difference.  The
old FS:FILE-xxx functions continue to work in system 53, but give an obsolete
function warning in the compiler and will be removed in system 54.

Documentation on pathnames is available.  The manual chapter on pathnames
is in the file AI:LMMAN;PATHNM >.  If you want to waste paper, you may
:DOVER LMMAN;PATHNM XGP.

There is a new terminal command, TERMINAL T.  Type TERMINAL HELP for
documentation.