Refactoring and Improvement of Unit Support

by Matthew Petroff for Inkscape

For Google Summer of Code, I would like to improve unit handling in Inkscape. It is my understanding that Inkscape's current unit handling is scattered across the code base in various locations, and from personal experience, I know Inkscape's unit handling could use improvement. To start, I would refactor all of Inkscape's unit handling into one centralized location. I would then extend this unit handling to allow for easier use of "real" units, e.g. millimeters, both on the document wide level and for individual objects.