* For the buttons, use id's instead of classes.
* Focus the "yes" button when the screen is shown.

issue #1582

* add network.prolongSession
* add user.setComputerOwnershipStatus and user.isUsersComputer. setComputerOwnershipSTatus calls network.prolongSession if called with true.
* in controllers/is_this_your_computer, call user.setComputerOwnershipStatus

issue #1349

* Add a unit test harness for is_this_your_computer
* When the user authenticates, set them as seen.
* In storage.js, Use an object to store the usersComputer info instead of arrays for developer grok.
* Add storage.js->clearUsersComputerOwnershipStatus for testing.
* Clean up user.js->logout a little bit.
* Completely clear localStorage between every test.
* Add tests to check for when the user should see the "is this your computer" screen.

rework how we decide when to ask about computer ownership: no is sticky for 24 hours.  only ask if it's been 1 minute since we first saw the user (not on the first login).  also defend against garbage in localstorage.

fix transition after answering the 'is this your computer' question - automatically complete signin after answering

wire up buttons of 'is this your computer' - functional but needs work (an extra click, figuring out all the places to ask the question, etc)

use a 'wait' screen for the is this your computer question, needs styling and yes and no buttons to do the right thing