Cleaned up some comments and whitespace

Removed gratuitous whitespace, and removed comments that no longer apply
to the current version of the grapher code, which no longer uses
GWT-G2D.
Fixed bug that blocked canvas resize

The correct way to resize a GWT canvas is to call setWidth() and
setHeight() on the result of canvas.getCanvasElement().  The previous
version of the code was calling canvas.setCoordinateSpaceWidth() and
canvas.setCoordinateSpaceHeight() instead, which didn't actually cause a
resize to occur.