Fix mixed-content warning when using Blue themes over HTTPS (#162)

The Blue themes' `base.html` hard-code the protocol used to retrieve
fonts CSS to `http`; this results in mixed-content warnings if the
site is served over HTTPS.

Remove this hard-coding so it uses the same protocol as that used to
access the site (Google's `fonts.googleapis.com` is accessible using
both).

src/leiningen/new/cryogen/themes/blue/html/base.html

@@ -5,8 +5,8 @@
     <title>{{title}}{% block subtitle %}{% endblock %}</title>
     <link rel="canonical" href="{{site-url}}{{uri}}">
     <meta name="viewport" content="width=device-width, initial-scale=1">
-    <link href='http://fonts.googleapis.com/css?family=Alegreya:400italic,700italic,400,700' rel='stylesheet'
-          type='text/css'>
+    <link href="//fonts.googleapis.com/css?family=Alegreya:400italic,700italic,400,700" rel="stylesheet"
+          type="text/css">
     <link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/css/bootstrap.min.css">
     <link href="//maxcdn.bootstrapcdn.com/font-awesome/4.2.0/css/font-awesome.min.css" rel="stylesheet">
     <link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/highlight.js/9.7.0/styles/default.min.css">

src/leiningen/new/cryogen/themes/blue_centered/html/base.html

@@ -5,8 +5,8 @@
     <title>{{title}}{% block subtitle %}{% endblock %}</title>
     <link rel="canonical" href="{{site-url}}{{uri}}">
     <meta name="viewport" content="width=device-width, initial-scale=1">
-    <link href='http://fonts.googleapis.com/css?family=Alegreya:400italic,700italic,400,700' rel='stylesheet'
-          type='text/css'>
+    <link href="//fonts.googleapis.com/css?family=Alegreya:400italic,700italic,400,700" rel="stylesheet"
+          type="text/css">
     <link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/css/bootstrap.min.css">
     <link href="//maxcdn.bootstrapcdn.com/font-awesome/4.2.0/css/font-awesome.min.css" rel="stylesheet">
     <link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/highlight.js/9.7.0/styles/default.min.css">