Wage loans for employers who cannot pay a living wage

This is phrased as a loan, as a benefit would violate state aid rules, probably. This might do as well, of course, need an expert opinion there. Also includes change from #223, as they are a prerequisite for this.
I suggest we change this to:
`The minimum wage should be set to the same value as the [living wage](http://www.livingwage.org.uk), and automatically adjusted in line with that figure.`

It's only going to get out of date and look bad otherwise :) Plus, I think the annual calculation (mine, originally IIRC) is wrong.