split doodling code off from the extension code.

the doodling stuff is now all inside the Doodle prototype. you can call
the constructor on any <svg> element, not just the outermost one, and
it should do the right thing. even if the element is rotated/skewed/etc.
added some properties so you can affect the Doodle.
allow Doodledoku to be called on any element, not just the body.

also allow options to use jQuery. and update options example script.