Recommend not to use any HTML for the main favicon

See <http://mathiasbynens.be/notes/rel-shortcut-icon>.

Also, recommend default file names for touch icons, as per <http://mathiasbynens.be/notes/touch-icons>.
Merge branch 'patch-1' of git://github.com/mathiasbynens/favicon-cheat-sheet into mathiasbynens-patch-1
Changes as per my comments in #11.