Generate Android update manifests in the libadblockplus format

[fhd]

Background

Android update checks are still using the old format, not the one used by libadblockplus (see #98).

What to change

Generate libadblockplus update manifests for Android on update.adblockplus.org.

Note that we need to keep generating updates.xml and androidupdates.xml for the foreseeable future - old versions of the app will still request those.

[fhd]

Pushed both patches, but it turns out the update.json format those generate is wrong. Here's how it looks currently:

[
  {
    "minSdkVersion": "7",
    "updateURL": "https://downloads.adblockplus.org/adblockplusandroid-1.2.1.apk?update",
    "revision": "318"
  }
]

Here's how it needs to look to work with the libadblockplus update mechanism:

{
  "adblockplusandroid": {
    "url": "https://downloads.adblockplus.org/adblockplusandroid-1.2.1.apk?update",
    "version": "1.2.1"
  }
}

Note that we will actually be working with the version then, instead of the revision. Also note that minSdkVersion would be ignored by the libadblockplus update mechanism, so I'm not adding it.

Adding a review that addresses this.

[fhd]

Another review - sorry for the mess. We also need to generate devbuild update manifests in the new format.

[fhd]

Pushed:
​https://hg.adblockplus.org/sitescripts/rev/60aa468c5362
​https://hg.adblockplus.org/sitescripts/rev/9fc54c28b4fd