Reapply no arg check in 1990/theorem

Due to a misunderstanding between Landon and me after some discussion on
GitHub it was recommended that I reapply this fix so I have done so.

I've updated the bugs.md file to change the definition of INABIAF (it's
not a bug it's a feature) as well as adding another known bug with this
entry to the file (this has also been added to README.md).

In bugs.md I also added towards the top a note to the winning authors
about fixes applied to their entries. Particularly if an author objects
to the fix we'll be happy to undo it even if it impacts the usability of
the program. There there is an apology too. We know there's a fine line
and although we have tried to use good judgement invariably some will be
the wrong decision. Thank you for understanding and apologies!

1990/theorem/theorem.c

@@ -23,7 +23,9 @@ C
 w(g,R,u)float*g,u;char R;
 /**/{int b,f;if(A>2){A=atoi(a[1]);b=atoi(a[2]);while((f=A+b)<15000){printf("%d\n",f);A=b;b=f;}}}
 main(A,a)int A;char*a[];
-o o
+o
+o
+if (a[1]==NULL||a[2]==NULL||a[3]==NULL||a[4]==NULL||a[5]==NULL) return 1;
 if(!strcmp(*++a,"-r"))S();
 D=atof(*++a);
 T=atof(*++a);