changes: Add 'Changes' section to track changes since previous versions of the spec

This commit also includes updated HTML CSS.

Change-Id: I0f45e3fba25587f97cbb63332d457baacb515f40
diff --git a/named_data_theme/theme.conf b/named_data_theme/theme.conf
index 1dab97e..aa5a7ff 100644
--- a/named_data_theme/theme.conf
+++ b/named_data_theme/theme.conf
@@ -6,6 +6,9 @@
 theme_bodyfont = "normal 12px Verdana, sans-serif"
 theme_bgcolor = "#ccc"
 
+theme_documentwidth = "100%"
+theme_textalign = "left"
+
 [options]
 
 stickysidebar = true