Add simplistic readable-mode buffer mode

conkeror/.conkerorrc/readable-mode.css

@@ -0,0 +1,18 @@
+body {
+    background-color: #ffffff;
+    color: #000000;
+    width: 750px;
+    margin: 0 auto;
+    font-family: Signika;
+    font-size: 16px;
+    text-align: left;
+}
+
+body img {
+    max-width: 750px;
+}
+
+pre, code, tt {
+    font-family: "Fantasque Sans Mono";
+    font-size: 16px;
+}

conkeror/.conkerorrc/readable.js

@@ -0,0 +1,26 @@
+/*global define_buffer_mode make_file read_text_file make_css_data_uri */
+
+var readable_load_path = this.loading_paths[0];
+
+function readable_mode_enable(buffer) {
+  var path = readable_load_path + '/readable-mode.css';
+  var file = make_file(path);
+  var styles = read_text_file(file);
+  var document = buffer.document;
+  var newCSS = document.createElement('link');
+  var uri = make_css_data_uri([styles]);
+
+  newCSS.id = 'readable-mode-css';
+  newCSS.rel = 'stylesheet';
+  newCSS.href = uri.spec;
+
+  document.getElementsByTagName('head')[0].appendChild(newCSS);
+}
+
+function readable_mode_disable(buffer) {
+  var newCSS = buffer.document.getElementById('readable-mode-css');
+  buffer.document.getElementsByTagName('head')[0].removeChild(newCSS);
+}
+
+define_buffer_mode('readable-mode', readable_mode_enable, readable_mode_disable,
+                   $doc = 'Make the current buffer readable.');