Add zopfli compression to advzip.

Build advzip with zopfli support like this:

	./autogen.sh
	./configure --enable-zopfli
	make advzip

And recompress a deflated file like this:

	advzip -i 100 -z example.zip

The -i parameter is the number of deflate iterations to run on each
archive member.
Add zopfli to the autotools templates.