Added configurations to `bumblebee` package to easy multiple monitors on Optimus
machines.
The behaviour of the default `bumblebee` package hasn't change, so this change
is backwards compatible. Users who want to connect a monitor to their discrete
card should use the package `bumblebee_display` instead.
Also added new configuration option to nixos bumblebee module:
```
hardware.bumblebee.connectDisplay = true
```
will enable the new configuration, but the default is still false.
* Bump bumblebee to 3.2.1
* Remove config.patch - options it added can be passed to ./configure now
* Remove the provided xorg.conf
Provided xorg.conf was causing problems for some users,
and Bumblebee provides its own default configuration anyway.
* Make secondary X11 log to /var/log/X.bumblebee.log
* Add a module for bumblebee
Note: it relies heavily on 'virtualgl'. This also makes the approach taken
by bumblebee not very effective.
So, this package is actually mainly useful for shutting down your card so that
it does not consume power/produce heat.
See the comments in bumblebee/default.nix
svn path=/nixpkgs/trunk/; revision=32036
