Changing hitOptions to the following sets only segments as selectable,
and increases the radius of the hit test.
var hitOptions = {
segments: true,
stroke: false,
fill: false,
tolerance: 500
};
Because paper.js uses the same HitResult function for segments,
handles, and whole items, just increasing the tolerance will increase
the hit radius for all selectable items. If you want everything
selectable, I'd think the easiest way would be to listen for modifier
key, and change the hitOptions accordingly.
The source files on the github project page have more documentation in
the comments.