* Fixed "Cursor Positions on Shared Whiteboards are Inconsistent".
The main fix is in the method cursor_point_to_space in
public/javascripts/spacedeck_whiteboard.js.
The calculation of the coordinates of the mouse pointer from absolute
window to the whiteboard space coordinates was incorrect.
There were a number of dependencies on this method which were updated
as a result.
One side-effect was that the div for the lasso tool needed to be
moved inside the div for the whiteboard.
* Fixed minor panning calculation problem. Works now!