Update to Cinnamon 1.8 settings API

[jonbrett]

The Cinnamon settings API was made available in Cinnamon 1.8. We should use it...

A good example/tutorial can be found on LinuxMint Segfault:
http://segfault.linuxmint.com/2013/05/applet-desklet-extension-settings-api-a-brief-example/

Using the new API gives us:

• Direct integration into cinnamon settings application
• Auto-generation of settings editing form (we can drop prefs.js)
• Ability to react to settings changes dynamically via callbacks
• Using the more stable applet API, which the Cinnamon devs try to keep stable (more stable than general Gnome stuff, not that Gsettings API is likely to go anywhere fast!)

The downside is that is is only available in Cinnamon >= 1.8. This shouldn't be a really big deal since Cinnamon 1.8 is available in most current distributions, is packaged with the current Linux Mint 15 and is even being backported to earlier versions of Linux Mint (13, 14 and LMDE) although I'm not sure when that will happen. I don't really want to make this change until 1.8 has been made widely available

[elbenfreund]

As this Issue documents the cinnamon applet is now maintained by the Mint Linux team.
As such this repository is kept around for historical and migration reasons.
Contributors are encouraged to head over there and no work will be done on this
repository at all.
Thanks for your support.