note old Email, header formatting, improve copyright and license

For the top level and year level README.md, where email are found,
a note was added to the effect that email addresses found above are
for historical purposes only, and should not be used today.

Old references to asking for fixes, comments, when content was used,
and next contest links were replaced with a general reference to the FAQ.

Harmonized the Copyright and License and copyright dates.
Now using Creative Commons "CC BY-SA 4.0 DEED Attribution-ShareAlike 4.0
International".

The above Creative Commons will become the standard for the IOCCC.
Replaced old `png/by-sa-3.0-88x31.png` with a new ` png/by-sa.88x31.png` icon.
Updated the top level HTML files to use the license.

1993/README.md

@@ -22,6 +22,7 @@ classic K&R C was allowed so long as ANSI C compilers could still
 compile the entry.  If you do not have an ANSI C compiler, you may
 not be able to compile the winners, sorry!
 
+
 ## A few notes regarding future contests:
 
 Be sure to wait until the 1994 rules are posted before submitting entries.
@@ -46,8 +47,12 @@ judges@toad.com
 If you use, distribute or publish these entries in some way, please drop
 us a line.  We enjoy seeing who, where and how the contest is used.
 
-If you have problems with any of the entries, AND YOU HAVE A FIX, please
-email the fix (patch file or the entire changed file) to the above address.
+**IMPORTANT NOTE**: The email addresses found above are for historical
+purposes only, and should not be used today.  See
+[contact.html](/contact.html) for up to date contact details
+as well as details on how to provide fixes to any of the entries.
+See also [the IOCCC FAQ](/faq.html) for addition information on the IOCCC.
+
 
 ### Credits:
 
@@ -55,10 +60,11 @@ We would like to thank Barbara Frezza for her role as official chef
 of the contest.  Landon Noll and Larry Bassel appreciated the opportunity
 to serve as official taste testers.  And as usual, the food was excellent.
 
-=-=
 
-Copyright (c) 1993, Landon Curt Noll & Larry Bassel.
-All Rights Reserved.  Permission for personal, educational or non-profit use is
-granted provided this this copyright and notice are included in its entirety
-and remains unaltered.  All other uses must receive prior permission in writing
-from both Landon Curt Noll and Larry Bassel.
+# Copyright and License
+
+Copyright (c) 1993,2023, Landon Curt Noll and Larry Bassel. All Rights Reserved.
+This work is licensed under a [Creative Commons CC BY-SA 4.0 DEED Attribution-ShareAlike
+4.0 International](https://creativecommons.org/licenses/by-sa/4.0/) license.
+If you do use this work in some form, the [IOCCC judges](/judges.html) would appreciate
+(but does not require) if you were to [send us a note about your use](/contact.html).