[Bug 33753] no 2D screensavers available

[Matthias Klose]

Public bug reported:
https://launchpad.net/malone/bugs/33753

Affects: gnome-screensaver (Ubuntu)
       Severity: Normal
       Priority: (none set)
         Status: Unconfirmed

Description:
the current selection doesn't contain any 2D screen savers; on hardware,
which doesn't support 3D graphics, that's just annoying. the screen
saver disables any power management and makes the computer behave like a
vacuum cleaner.

proposed solution:
- include 2D screen savers (and mark them as not CPU intensive)
- run screen saver nice'd, so it doesn't influence power management