Kde 4.13.1

**Do not merge yet!**
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This adds KDE 4.13.1 as kde4_next, as well as adding kde4_next as a desktopManager option. I'm using it, the base functionality works.

However, there are still loose ends:
- Not everything builds, although the base desktop works
- It upgrades kde-telepathy, not sure if that breaks other packages that depend on it
- It doesn't build Nepomuk, because I was under the impression that Baloo supersedes it, however a bunch of packages still use it, and they are pulling it in from somewhere else :sweat_smile: 
- kde_workspace is still 4.11.6 and I'm not sure if there is a newer version to be pulled from somewhere other than the stable tarballs. Confusing. I do know that the Dsplay settings module on Ubuntu 14.04 is quite different from the kcm_display one in kde_workspace.
- I haven't checked all the build logs to find optional dependencies to add, or remove. Mostly the tree is a copy of the 4.12 one with adjustments to make things build.
- the kadu package was already broken before 4.13, it can't find phonon at build time for some reason (it's there and so is pkgconfig)

So this is a preview and an invitation for comments.