draw only one block per ring

This is some preparation to be able to swap blocks easier.
add module to represent board state
add makeBoard function to start creating model
move board.js to board/model.js
add separate view script file
move selector drawing into the view module
move ring drawing to view module
rotate cube to the front
render blocks by using the model
rename ring.js to block.js

It no longer renders a ring of blocks but just one block.
draw selector on top of blocks
rename block.js to cell.js
support different block styles again
draw multiple rings again
pull some constants out to a common module
put movement handling code into the model
remove some extraneous commas
remove keycode.js

Can't use the objects with dot notation as keys so remove this for now.
update Makefile to grab sources in nested dirs
update compiled javascript