Major revision of comment system.

- Comments are stored in HTML as well as Markdown, so that conversion
  only happens when saving (rather than when viewing).
- Added 'markdown' Jinja filter for easy development. This is quite
  a heavy filter, so it shouldn't be used (much) in production.
- Added CLI command to update schemas on existing node types.

src/scripts/tutti/6_jquery_extensions.js

@@ -0,0 +1,42 @@
+(function ( $ ) {
+    $.fn.flashOnce = function() {
+        var target = this;
+        this
+            .addClass('flash-on')
+            .delay(1000) // this delay is linked to the transition in the flash-on CSS class.
+            .queue(function() {
+                target
+                    .removeClass('flash-on')
+                    .addClass('flash-off')
+                    .dequeue()
+                ;})
+            .delay(1000)  // this delay is just to clean up the flash-X classes.
+            .queue(function() {
+                target
+                    .removeClass('flash-on flash-off')
+                    .dequeue()
+                ;})
+        ;
+        return this;
+    };
+
+    /**
+     * Fades out the element, then erases its contents and shows the now-empty element again.
+     */
+    $.fn.fadeOutAndClear = function(fade_speed) {
+        var target = this;
+        this
+            .fadeOut(fade_speed, function() {
+                target
+                    .html('')
+                    .show();
+            });
+    }
+
+    $.fn.scrollHere = function(scroll_duration_msec) {
+        $('html, body').animate({
+            scrollTop: this.offset().top
+        }, scroll_duration_msec);
+    }
+
+}(jQuery));