Add svgPath output function, added arcFrom shorthand, added path draw opt

I have added a SVG generator function that logs the path to SVG for creating PNGs or such.
I have added an autojoin turn off setting to disable automatic insertion of lineTo after arc.
I have added coordinate rounding for performance.
New options:
	logSvg:true, 
	autoJoinArcWithLineTo: false,
        floorCoordinates:false         // turn off antialias on canvas, improve speed

New function arcFrom(x, y, ...