update year level .filelist

Added new YYYY/index.html files.

Removed var.mk as such special top level files are
added (or not) in various bin tools.

2015/.filelist

@@ -6,8 +6,8 @@
 2015/.gitignore
 2015/guidelines.txt
 2015/hint.css
+2015/index.html
 2015/iocccsize.c
 2015/iocccsize.mk
 2015/rules.txt
 2015/.year
-var.mk