Automatically disable animations when software-rendered

[Sergey "Shnatsel" Davidoff]

Gala should automatically disable animations when it finds itself software-rendered.

The animations bool in GSettings should be converted to an enum with "enabled", "disabled" and "auto" options; in "auto" mode (default) Gala should check CLUTTER_COGL_HAS_GL constant to determine if it's software-rendered or not, and if yes, disable animations.

I couldn't find any documentation on that variable, so we might need additional testing to determine if llvmpipe counts as hardware acceleration (in theory it should not).

ProblemType: Bug
DistroRelease: elementary OS 0.2
Package: gala 0.1-0~r290+pkg16~custombuild
ProcVersionSignature: Ubuntu 3.5.0-19.30~precise1-generic 3.5.7
Uname: Linux 3.5.0-19-generic x86_64
ApportVersion: 2.0.1-0ubuntu17.1+elementary3~precise1
Architecture: amd64
CrashDB: gala
Date: Sun Feb 10 15:12:41 2013
GsettingsChanges:

InstallationMedia: elementary OS 0.2 "Luna" - Build amd64 LIVE Binary 20121001-15:16
MarkForUpload: True
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 LANG=ru_RU.UTF-8
 SHELL=/bin/bash
SourcePackage: gala
UpgradeStatus: No upgrade log present (probably fresh install)