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commented and beautified
added more functions

fixed errors, renamed render.js to display.js, moved "keyPress" to
controls.js
and added:
(1) p = pause/unpause
(2) space = hard drop
(3) esc = new game
fuxed detached head
fixed detached head issue
more comments

and some beautification
solved merge issue
Merge branch 'master' of https://github.com/mendelthegeek/my-canvas-tetris
another issue!