Sort WOFF2 before WOFF by default, recommend WOFF2

Apparently browsers process the list of fonts in-order and stop at the
first supported option. For this reason, it does not make sense to put
WOFF2 after WOFF when generating both, as reported in #21. Instead,
change the order of the 'all' default format to start with WOFF2 and
WOFF, sort the older formats towards the end and change the
recommendation to use WOFF2 and WOFF.

Closes: #21

README.md

@@ -42,9 +42,13 @@ the terms.
         webfont formats. Supported identifiers are <code>eot</code>,
         <code>woff</code>, <code>woff2</code>, <code>svg</code>, and
         <code>ttf</code>. Additionally, the special value <code>all</code>
-        expands to all supported formats. The default is <code>all</code>. Note
-        that you may not really need all formats. In most cases, WOFF is enough.
-        See http://caniuse.com/#search=woff for a current status.</dd>
+        expands to all supported formats in the order <code>woff2</code>,
+        <code>woff</code>, <code>eot</code>, <code>svg</code>,
+        <code>ttf</code>. The default is <code>all</code>. The generated CSS
+        file will contain the font formats in the given order, which browsers
+        will process in-order. Note that you probably do not need all formats.
+        In most cases, a combination of WOFF2 and WOFF is enough. See
+        http://caniuse.com/#search=woff for a current status.</dd>
     <dt><code>-h</code>, <code>--help</code></dt>
     <dd>Display this message and exit.</dd>
     <dt><code>-l LANGSPEC</code>, <code>--languages=LANGSPEC</code></dt>

google-font-download

@@ -70,10 +70,13 @@ usage() {
 		    servers. FORMAT is a comma-separated list of identifiers for
 		    webfont formats. Supported identifiers are eot, woff, woff2,
 		    svg, and ttf. Additionally, the special value \`all' expands
-		    to all supported formats. The default is \`$format'. Note
-		    that you may not really need all formats. In most cases,
-		    WOFF is enough. See http://caniuse.com/#search=woff for
-		    a current status.
+		    to all supported formats in the order woff2, woff, eot, svg,
+		    ttf. The default is \`$format'. The generated CSS file will
+		    contain the font formats in the given order, which browsers
+		    will process in-order. Note that you probably do not need
+		    all formats. In most cases, a combination of WOFF2 and WOFF
+		    is enough. See http://caniuse.com/#search=woff for a current
+		    status.
 
 		  -h, --help
 		    Display this message and exit.
@@ -308,7 +311,7 @@ fi
 declare -a formats
 if [ "$format" = "all" ]; then
 	# Deal with the special "all" value
-	formats=("eot" "woff" "woff2" "svg" "ttf")
+	formats=("woff2" "woff" "eot" "svg" "ttf")
 else
 	IFS=', ' read -r -a formats <<< "$format"
 	for f in "${formats[@]}"; do