uhc: remove broken package

https://github.com/NixOS/nixpkgs/issues/3565
idea-{community,ultimate}: 13.1.5 -> 14pre
linux: Update testing 3.17-rc2 -> 3.18-rc3
Merge pull request #4770 from titanous/linux-testing

linux: Update testing 3.17-rc2 -> 3.18-rc3
ristretto: wrap icon theme