Many improvements including: * upgraded jquery to latest version, with the jquery-migrate helper library, to get rid of the warning about preventDefaults; * smany changes to halfviz (since I'm using it as a library in by GWT / GXT app) such as suppressing the IO class use of jquery-address if the IO panel is not used; * fixed a bug in the parser after upgrading to new jquery; * added a pick(x,y) function to find the node under the given point (e.g., mouse click); * cleaned up halfviz node dragging to use pick instead of nearest, and to move the node based on where I grabbed the node (rather than snapping node center to mouse)