New section login pages

New way to log in to a section using a 'secret picture' or 'secret word':

<img src="https://www.dropbox.com/s/aldug6jp7u27dsg/Screenshot%202014-07-24%2015.18.02.png?dl=1">

<img src="https://www.dropbox.com/s/oirq2zkkcfa2tvl/Screenshot%202014-07-24%2015.18.17.png?dl=1">