Allow Inkscape to draw using a string as input

At the moment, Inkscape does not allow users to enter commands to Inkscape in a text-based format. This specification proposed to add that functionality, both at the command line and internally, possibly using a command-line box similar to Rhino's. In this way, a user will be able to directly enter precise instruction to Inkscape with minimal effort. For example, a command such as "circle r:50" could be entered and Inkscpae will produce a circle of radius 50px, with all other attributes set to default values. In this way, technical drawing becomes easier, and the interface to Inkscape from external programs is vastly increased.