Correctly mark ROM and RAM banks for Master. Fixes #31 and #25
jslint fixes
Handle noise writes correctly

That is, data writes to the sound chip when the noise register is
selected don't set the top bits (as they do for tone registers) but
instead write the low bits still.

This fixes Crazee Rider and inasmuch as I can tell, Snapper too, and
so closes #23.
natural & gaming keymaps
#4 fix for " ~ @ on US keyboards (hopefully)
#4 another attempt to fix US keyboard
#4 missing keycode (220 \|)
Fix TST handling. Add historical register values.
formatting
Clarify home key
IDEA notices a new git root
Add a physical layout and UI to pick between layouts
Fix up initial key layout
Map left shift in physical mode
#4 tidying keyboard code
Fix local discs and disc writes. Fixes #37
more generous thresholds for XBox 360 controller
New CSS and screen size to allow better positioning.

Image is now behind the cub monitor instead of surrounded by it. I've
fiddled about a bit and tweaked the visible portion to match
photographic evidence, and to get Boffin working (fixes #26).

Elite looks a lot better too.
allow custom keycode mapping in URL eg ?KEY.LEFT_SQUARE_BRACKET=AT
allow mapping of Gamepad buttons in URL, eg
?GP.LEFT1=CAPSLOCK&GP.RIGHT1=CTRL&GP.A=RETURN&disc=%7CAardvark%2FZalaga.zip&autoboot