Created branch for rhythmbox GTK+3.
I've tried to update the rhythmbox-ampache plugin to be used in Rhythmbox 2.95 (and up) and would like to provide my changes in the attached patch for review and possibly a new branch in this repository.

I based the plugin on HEAD of this repository but used various parts/ideas from the now dysfunct Magnatunes plugin. Major changes are:
- GSettings are used for storing plugin preferences.
- The preferences GUI has been updated. The server url takes now the ampache root and omits the server/xml.server.php extension.
- Refetching is done through the context menu of the entry. The xml file downloaded from the server is used directly as cache file.
- The xml is parsed using sax.

Things I'm not too happy about and will need to be changed:
- rhythmbox entry_delete_by_type() results in an entry->refcount > 0 assertion and Segmentation Fault and therefore do_deactivate() leaves this call out; refetch will cause a Segmentation Fault at this moment because of that
- I would have liked to use Gio for writing the cache file (I use it for downloading the songs information and loading the cache file) but write_async seems to cause garbage at the beginning of each chunk; I'm using python file I/O as a workaround
- I haven't touched the README file

I'm using the plugin myself successfully at the moment.

For information: I've sent in a patch to ampache that should accelerate the xml API songs download to make this plugin more attractive to use.

Any comments are of course very welcome.
Fixed install paths.
Fixed indentation.
Changed file write from GIO to native python file I/O.
Changed handling of urls from cache:
The auth string from the handshake replaces the cached auth/ssid strings.
This improves ampache session handling.
Moved all files one level up (removing the unnecessary subdirectory ampache).
Event do_selected calls do_activate (single click will activate the plugin).
Added year support.
Added error in case of empty handshake response.
Changed download criteria to take all three times (update, add, clean) into account, rather than just update.
Added support for Ampache Playlists.
Restructured some code.
Reintegrated check for add and clean times (r33:34).
Added cleanup code.
Included workaround for maintaining a separate song entries list as even after an entry has been created in the database, dereferencing the entry unrefs it.
Todo: clear entries list at some sane point as it will grow with each update. Clearing it directly after entry_delete_by_type is called will clear the references too quickly.
Changed refetch handling for 2.99.
Refetch not working but the rest of plugin works.
Toolbar menu works now.