Full keyboard control

[soup-bowl]

Bringing back a point raised in issue #19 .

For a wallboard that needs interaction, it would be preferable to only need to use one input device. At the moment, tab controls depend on whether they're accessing the IFrame or the parent, in which case the parent does not react well anyway.

What will be handy is for some keyboard shortcuts for all the dock features, minimising the need for the use of a mouse.