add make genpath rules, .path files, updated .top and .year

Add .path files to each winner directory: a file containing
the path to the winner directory from the top directory.

Changed YYYY/.year files to contain the paths, from the top
directory, if the winning directories for the given year.

Changed `/.top` to contain the IOCCC years.

Added `make genpath` rule to the top Makefile and the
year Makefiles to generate the above.

Added FAQ 6.8 to `faq.md` to explain the above.

Updated manifest to reflect recent changes to the list of files.

2001/.year

@@ -1 +1,15 @@
-2001
+2001/anonymous
+2001/bellard
+2001/cheong
+2001/coupard
+2001/ctk
+2001/dgbeards
+2001/herrmann1
+2001/herrmann2
+2001/jason
+2001/kev
+2001/ollinger
+2001/rosten
+2001/schweikh
+2001/westley
+2001/williams