Show landing page with release notes after upgrading AVIM

[1ec5]

Years ago, when a new version of AVIM came out, Firefox would tell you what’s new before you installed the update. Nowadays the upgrade happens silently, so users have no idea how much AVIM has improved in the past 5–6 years. The first time you open Firefox after upgrading AVIM, we should display the latest release notes. Along these lines, the first time you open Firefox after installing AVIM, we should display Typing in Vietnamese.

[1ec5]

The landing page would use this call to fetch all the release notes:

$.ajax("https://api.github.com/repos/1ec5/avim/releases", {
    ifModified: true,
    complete: function (data) {
        console.log(data.responseJSON[0].body);
    }
});

Then body would be parsed by something like markdown-js.

[1ec5]

As of 8181aeb715828d9f9c9a11f4ebb3f4ff78d2d0a1, the landing page is now live. All that remains is to show it on first run.