Restore missing 2018/README.md from 2018 preview

For some reason this was missing from the repository. I was certain that
there was one so I looked at my archive and found in the winner preview
repo for 2018 that there was indeed a README file (README.markdown).
This has been added as 2018/README.md. It felt important that this was
added back.

I did NOT update the 2018 archive tarball as I'm not sure what to even
call it - perhaps just README.markdown - but also because I'm not sure
what the status is of my archive/2018 is.

I fixed the formatting to match the style that is being used in this
repo.

2018/README.md

@@ -0,0 +1,113 @@
+# 2018 marked the "The Twenty Fifth International Obfuscated C Code Contest"
+
+Copyright (C) 2018, Landon Curt Noll, Simon Cooper, and Leonid A.
+Broukhis. All Rights Reserved. Permission for personal, educational
+or non-profit use is granted provided this copyright and notice are
+included in its entirety and remains unaltered.  All other uses
+must receive prior permission from the contest judges.
+
+
+## Standard IOCCC stuff
+
+The primary IOCCC web site can be found at,
+
+>	<https://www.ioccc.org/>
+
+Use make to compile entries.  It is possible that on non-Un\*x / non-Linux
+systems the makefile needs to be changed.  See the Makefile for details.
+
+Look at the source and try to figure out what the programs do, and run
+them with various inputs.  If you want to, look at the hints files for
+spoilers - this year we included most of the information included
+by the submitter.
+
+Read over the makefile for compile/build issues.  Your system may require
+certain changes (add or remove a library, add or remove a #define).
+
+Some C compilers are not quite as good as they should be.  If yours is
+lacking, you may need to compile using clang or gcc instead of your local
+compiler.
+
+
+## Remarks on some of the winners
+
+We believe you will again be impressed with this year's winners.
+
+The "Best of show" (mills) is an amazing tribute to winners
+from 1984 and 2015.
+
+Take a close look at the "Most likely to top the charts" (hou) winner.
+Observe that while it contains no variables and no operators, it
+remains functional in what it does.
+
+The "Best one-liner" (burton1), at 109 characters, is a short and sweet
+implementation of a classic utility and a nod to a winner from 1986.
+Sometimes it takes 20 ox years to do things the true IOCCC way.
+
+The color of the remarks text this year was inspired by one of the stars
+of the "Most stellar" winner (poikola).
+
+The "Best use of python" (endoh2) is a not what you might think it is.
+It is something completely different.
+
+The "Most likely to be awarded" (ciura) has an amazing vocabulary!
+
+There are also nods to winners of the years 2000 (bellard), 1989 (yang), ...
+
+...We'll stop spouting spoilers now. Have fun exploring all the entries!
+
+
+## Remarks on some of submissions that did not win
+
+The number of entries that would have made it into the final rounds
+would have been much higher had some people paid attention to rules 2
+and 22 (one third of 666).
+
+Rule 22, now known as "Catch 22" states:
+
+    |  22) Your source code, data files, remarks and program output must NOT
+    |      identify the authors of your code.  The judges STRONGLY prefer to
+    |      not know who is submitting entries to the IOCCC.
+
+    |      The "Peter Honeyman is exempt" guideline also applies to this rule.
+    |      Identifying yourself, in an obvious way in your code, data, remarks
+    |      or program output, unless you are Peter Honeyman or pretending
+    |      to be Peter Honeyman, will be grounds for disqualification of your entry.
+
+A number of other entries were based on iocccsize.c, making derivative works
+rather than original works.
+
+Still other entries were too large, violating the first line of rule 2:
+
+    2) The size of your program source must be <= 4096 bytes in length.
+
+While these entries might have passed under the 2053 limit for iocccsize,
+they were larger than <= 4096 bytes, sometimes by an order or magnitude.
+
+We hope the authors of some of those entries will fix and re-submit
+them for the next IOCCC.
+
+Some entries seemed to have a good idea, but the implementation of
+the idea was limited in scope.
+
+
+## Final Comments
+
+Please feel free to send us comments and suggestions about the
+competition, this README or anything else that you would like to see in
+future contests.
+
+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
+send us the fix (patch file or the entire changed file).
+
+For the latest information on how to contact the IOCCC Judges please visit
+
+>	<https://www.ioccc.org/contact.html>
+
+For news of the next contest watch:
+
+>	<https://www.ioccc.org/>
+