PartKAM is a browser-based 2.5d CAM program I wrote circa 2010. Originally hosted on launchpad (this was before github was a thing)
It imports SVG files and exports Gcode for CNC machining, featuring sketch-based CAD tools, a novel offset algo, and a rudimentary nesting function.
try it out here: http://partkart.com
or here: http://makercam.com
some discussion on this old CNCzone thread: http://www.cnczone.com/forums/opensource-software/106198-partkam-free-crossplatform-2-5d-cam.html
An offset algorithm that leverages the flash rasterizer
A simple nesting system based on raster-collision detection