Add "download groups"

[Barry Warsaw]

I think we need to be able to group individual downloads together. After discussion with didrocks about how the new u/i will work, having groups will help make the experience better. Here's a rough outline:

- the u/i will request from the client to download the current update in the background
- this update may include the download of many files
- we request a download group, and add all those individual downloads to it
- now the client can exit, after passing the group id to the u/i
- the u/i can then request progress on the group of downloads; once it's seen them all complete successfully, it re-fires the client and tells it to apply the update
- the client can use the persisted group id to get access to all the local files participating in the group
- it moves the local files into the right place and issues the reboot

[Launchpad Janitor (janitor)]

This bug was fixed in the package ubuntu-download-manager - 0.2+13.10.20130826-0ubuntu1

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ubuntu-download-manager (0.2+13.10.20130826-0ubuntu1) saucy; urgency=low

  [ Manuel de la Pena ]
  * Middle step to fix #1211838 that refactors the code so that we have
    a base Download class that is used by the DownloadQueue that can is
    later extended by a single download class and a group download
    class. (LP: #1211838)

  [ Ubuntu daily release ]
  * Automatic snapshot from revision 102
 -- Ubuntu daily release <email address hidden> Mon, 26 Aug 2013 18:03:57 +0000

[Launchpad Janitor (janitor)]

This bug was fixed in the package ubuntu-download-manager - 0.2+13.10.20130830-0ubuntu1

---------------
ubuntu-download-manager (0.2+13.10.20130830-0ubuntu1) saucy; urgency=low

  [ Manuel de la Pena ]
  * Second part of the fix for #1211838. In this branch we add a
    GroupDownload object that takes care of dealing with a collection of
    urls to download as an atomic operation. (LP: #1211838)

  [ Ubuntu daily release ]
  * Automatic snapshot from revision 104
 -- Ubuntu daily release <email address hidden> Fri, 30 Aug 2013 02:03:56 +0000