Don't round calculation of rowHeight and columnWidth in the drawGrid function. If you want to plot points on the drawn grid, rounding these figures will lead to inaccuracies.
Signed-off-by: Dmitry Baranovskiy <dmitry.baranovskiy@gmail.com>

Rewrite transformation part (again) for SVG.
Small code improvements.

Fixed couple of bugs for IE, especially with changing attributes for x and y. Added colour functions rgb2hsb & hsb2rgb. Also included fix by netnichols.

attr("name") returns current value for attribute
scale(x, y) scales object horizontally and vertically, use negative values to reflect
some bug fix.