[development] Patching settings.php

[Rowan Kerr]

Gerhard Killesreiter wrote:
> The problem is that the installer writes to the file in 
> default/settings.php. The installer should create an appropriate 
> subdiretory /mydomain and then copy the settings.php file there and 
> write to the copy.

So we'll need another option in the installer to specify the hostname of 
the site being installed, yeah?

-Rowan