Renames existing `alphanumeric` sorting method to `label` and adds a new method called `name` which uses the real workspace name, akin to behaviour before #799.
BREAKING CHANGE: The workspace `sort` config option valid values have changed. Where `alphanumeric` is explicitly set, this will need changing to one of `label` or `name`.
BREAKING CHANGE: To allow for the `name` property, any widgets that were previously targeted by name should be targeted by class instead. This affects **all modules and all popups**, as well as several widgets inside modules. **This will break a lot of rules in your stylesheet**. To attempt to mitigate the damage, a migration script can be found [here](https://raw.githubusercontent.com/JakeStanger/ironbar/master/scripts/migrate-styles.sh) that should get you most of the way.
Resolves#75.
