[Grace-core] Updated Objectdraw Libary

[Kim Bruce]

I have just committed an updated version of the objectdraw library for Grace.  You will recall that this is a library designed to support object-oriented graphics and event-driven programming, and is based on a similar library in Java that I co-authored years ago.  It can be found in directory Objectdraw 2013.

There are two main changes from the previous version:
1.  This version of objectdraw takes advantage of the corrected semantics of Grace.  As a result, the programmer no longer must (and should not) put a request for doSetUp as the first item in a GraphicApplication.  Instead that will be called automatically from the superclass.

2.  I have updated the names of classes to make them more consistent.  All classes now start with "a" rather than some with "Mk" and others with nothing at all.  Thus you will find classes "aLocation", "aFramedRect", etc.

The instructions for using it have been updated as well.  Please let me know if you see any problems.

Kim