moves template setup code into _setupTemplate method in GamePage
renames _initialiseTemplate to _populateTemplate in GamePage
adds premove pref to User
adds board_click event to game_page.html for cancelling premove on right click
adds parent parameter to _setupTemplate in GamePage
changes template to fire cancel_premove on-contextmenu in GamePage and moves handler to _setupBoard
adds event.original.preventDefault() to cancel premove handler to stop right-click menu appearing
adds premove method to Game.  still need cancelPremove and a way of the
user getting their current pending premove if they refresh the page
adds some basic premove functionality to GamePage.  still need to
be able to cancel them, apply the existing one when the user first
comes to the page, and make sure the highlighting is cleared when
the opponent moves etc