Option to override default distro ascii art

[pbone64]

Description

A config option that lets you override the default distro ascii art displayed would be useful. Windows has three different styles of ascii art that may be preferred by different users and manually overriding the distro can be used to work around #29.

I understand that the --distro option exists, but if we allow specifying a default flag I don't see why the same can't be done for distros.

[hykilpikonna]

The configuration file isn't meant to be manually edited though, but here it is anyways.

You can now add "distro" keyword in config to specify a distro :)