Set one a one-year Cache-control: max-age header for fonts.

Sets "Cache-control: max-age=31536000" header for font files under
docroot/bits/w/extensions. Font files are detected by their extension, using a
<FilesMatch> directive. Font extensions are ttf, eot and woff.
This is primarily intended for UniversalLanguageSelector.

Change-Id: Id362b24ab01482dcd16b1c7f43e52b38de06a975