* Added new optional previous_revision params to default(), contents() and load_note() in controller.Notebooks.
These use Html_differ() to generate and return diffs.
* Updated Wiki.js:
* provide previous_revision when a revision is opened in a new window/tab
* call load_note() when two revisions when a revision is clicked in Changes_pulldown
* update compare_versions() to display a diff instead of opening the two revisions separately
* update load_editor():
* update all invocations of load_editor(), including in Editor.js, to accept a new previous_revision argument
* modify load_editor() to use the previous_revision argument (when supplied) to load a diff
* If a phrase becomes italicized, it should show the non-italic version in red and immediately after, the italic
version in green.
This required doing a pass on the HTML to merge certain elements together before doing the actual diff.
strings. Not perfect yet. For instance, if string a contains "foo bar baz" and
string b contains "foo <i>bar</i> baz", the resulting output does not show
"bar" in strikeout and "<i>bar</i>" in green, as one might expect.
* Implemented new controller.Notebooks.load_recent_updates() method.
* Added new Wiki.js total_notes_count_updated signal
* Added "more" and "less" links to "recent updates" table.
* Updated Wiki.js Recent_notes to support new "more" and "less" links.
* Commented out unfinished discussion forums unit test.
* controller.Notebooks now takes (and stores) an https_url constructor parameter.
* New controller.Notebooks.updates() method to produce an updates RSS feed for a particular notebook.
* New controller.Notebooks.get_update_link() method to make a brief page with just a link for an updated note, referred to by the feed.
* Implemented views for the new RSS feed.
* Fixed bug in Rss_item's guid that caused newlines to be inserted before and after long URLs.
* Still need to unit test new controller code.
* Put all expanders into <div>s, which are then wrapped in <td>s. This makes for better vertical centering, especially in IE.
* Modified Wiki.js to account for expanders now having yet another parent.
* Put note tree instructions in a <tr><td> instead of in a <div>, as <div>s alone don't belong in tables.