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.

2011/.year

@@ -1 +1,14 @@
-2011
+2011/akari
+2011/blakely
+2011/borsanyi
+2011/dlowe
+2011/eastman
+2011/fredriksson
+2011/goren
+2011/hou
+2011/konno
+2011/hamaji
+2011/richards
+2011/toledo
+2011/vik
+2011/zucker