fix #1496 : Asset hashes on WOFF vs WOFF2 fonts get confused

reverse sorting the extensions regex solves this issue

middleman-core/features/asset_hash.feature

@@ -47,6 +47,15 @@ Feature: Assets get a file hash appended to their and references to them are upd
     And the file "subdir/api.json" should contain 'images/100px-5fd6fb90.jpg'
     And the file "subdir/api.json" should contain 'images/100px-1242c368.png'
 
+  Scenario: Hashed fonts assets work with woff and woff2 extension
+    Given a successfully built app at "asset-hash-app"
+    When I cd to "build"
+    Then the following files should exist:
+      | fonts/fontawesome-webfont-56ce13e7.woff |
+      | fonts/fontawesome-webfont-10752316.woff2 |
+    And the file "stylesheets/uses_fonts-88aa3e2b.css" should contain "src: url('../fonts/fontawesome-webfont-10752316.woff2')"
+    And the file "stylesheets/uses_fonts-88aa3e2b.css" should contain "url('../fonts/fontawesome-webfont-56ce13e7.woff')"
+
   Scenario: Hashed assets work in preview server
     Given the Server is running at "asset-hash-app"
     When I go to "/"

middleman-core/fixtures/asset-hash-app/source/stylesheets/uses_fonts.css

@@ -0,0 +1,4 @@
+@font-face {
+  font-family: 'FontAwesome';
+  src: url('../fonts/fontawesome-webfont.woff2') format('woff2'), url('../fonts/fontawesome-webfont.woff') format('woff');
+}

middleman-core/lib/middleman-more/extensions/asset_hash.rb

@@ -63,7 +63,7 @@ class Middleman::Extensions::AssetHash < ::Middleman::Extension
       @rack_app        = app
       @exts            = options[:exts]
       @ignore          = options[:ignore]
-      @exts_regex_text = @exts.map { |e| Regexp.escape(e) }.join('|')
+      @exts_regex_text = @exts.map { |e| Regexp.escape(e) }.sort.reverse.join('|')
       @middleman_app   = options[:middleman_app]
     end