Revisit 1990 entries

Although I previously got them to all compile they did not all work. Now
they do except that jaw does not work properly in macOS (I have noticed
something odd in linux too but it appears to work mostly if not
entirely).

Yusuke Endoh pointed out for 1990/theorem that atof() nowadays needs
include stdlib.h so this was added to the file. As well I added the
inclusion of string.h for strcmp(). I also fixed some segfaults in this
entry (even though the judges pointed out that for NULL pointer one
needs the four '0 0 0 0' it still segfaulted under those conditions) so
that everything should work now under both linux and macOS. There were
iirc two parts to this: one the NULL pointer is no longer dereferenced
but also the type being passed to strcmp() was a int * and not a char *.
This prevented 1990/theorem/sorter from working at all (segfault) and as
I recall it there was another segfault I encountered as well.

For 1990/jaw Yusuke Endoh provided a ruby implementation of btoa as it's
not always available in modern systems. Thank you Yusuke!

In 1990/jaw shark.sh had to be modified as well. This had to do with '.'
not being in the default PATH.

As well I had previously made a mistake about btoa versus atob as both
were referenced in 1990/jaw/README.md. I believe I have this correct
now.

Many if not all the README files were modified with various changes
including formatting (like turning them into markdown) and section
titles amongst other things.

I seem to recall I'm missing something here but I can't recall what I
recall :-) so this will have to suffice this time round (maybe it was
the btoa/atob issue that I just remembered and added above but I'm not
sure).

1990/tbr/README.md

@@ -1,10 +1,17 @@
 # Best Utility
 
-	Byron Rakitzis	       Sean Dorward
-	Princeton University   Princeton University
-	5707 Old Lodge Dr.     10274 Burleigh Cottage Lane
-	Houston, TX 77066      Ellicott City, MD 21043
-	USA		       USA
+	Byron Rakitzis	       
+	Princeton University   
+	5707 Old Lodge Dr.     
+	Houston, TX 77066      
+	USA		       
+
+	Sean Dorward
+	Princeton University
+	10274 Burleigh Cottage Lane
+	Ellicott City, MD 21043
+	USA
+
 
 ## To build:
 
@@ -16,13 +23,16 @@
 
 ## Judges' comments
 
-    This program implements a subject a well known Un*x utility whose 
-    original source was considered to be extremely obfuscated by many
-    people, excluding its author.  In fact, this utility was a major
-    inspiration for the formation of this contest.
 
-    The author supplied us with a slightly smaller unformatted version
-    of the program which we include below:
+This program touches on a well known Unix utility, the 6th edition Bourne Shell
+(`/bin/sh`), whose original source was considered to be extremely obfuscated by
+many people (although Steve Bourne might disagree). Did you know that the Bourne
+Shell source was a major inspiration for the formation of the IOCCC back in
+1984?
+
+
+The author supplied us with a slightly smaller unformatted version
+of the program which we include below:
 
 	    #define D ,close(
 	    char*c,q[512],m[256],*v[99],**u,*i[3];int f[2],p;main(){for(m[m[60]=m[62]=
@@ -36,9 +46,10 @@
 	    e(x){x<0?write(2,"?\n$ "-x/4,2),x+1||(exit(1),0):5;}
 
 
-    Modern compilers had a problem with this entry because the exit(3) function
-    returns void but we were able to get it to compile by using the comma
-    operator which we also did in the smaller version.
+Modern compilers had a problem with this entry because the exit(3) function
+returns void but we were able to get it to compile by using the comma
+operator which we also did in the smaller version.
+
 
 ## Author's comments