The current config file layout cannot be serialized to TOML with serde,
so switch to YAML. This necessitates updating to an unreleased
version of confy. See: alexcrichton/toml-rs#145 and
alexcrichton/toml-rs#407.
Print out the location of the default config file upon creation see:
fixes #73, fixes #78.
Set the default left prompt to something so the user isn't left
scratching their head.
Change the default icon set to Unicode so that this is usable out of
the box with as few dependencies as possible.